Talos

Of course they were. That was pretty standard at the time in the US. You can see them fitted in other gunports here on USS Portsmouth, Jamestown, Kearsarge, and others. Though the ones in the regular gunports were probably only fitted in port, I would imagine that the stern windows were probably fitted any time they weren't cleared for action (at which time they would disassemble the captain's cabin). They probably had blank wood plugs they could put there too for stormy weather.
 
http://www.navsource.org/archives/09/86/098602502.jpg
http://usgwarchives.net/va/portsmouth/shipyard/ships/jamestown/jamestown4.jpg
http://www.navsource.org/archives/09/86/098617628.jpg
http://www.wrecksite.eu/img/wrecks/z_a_usstrenton1876.jpg

They're ports with window inserts when the ship isn't cleared for action, yes.

That’s actually not a quarterdeck, that’s a poop deck. The ship already had a quarterdeck, it’s the aft section of the spar deck.
 
I don’t think they kept the aft pivot though. The aft pivot is definitely not up on the poop cabin’s roof. You can see in the photo that the spanker boom attached to the mizzen is still in the same place. I really do think they stuck with the same four ports on each deck on the stern, not a specially-wider port for the pivot. If you look at the picture of her stern with the boat, you can see one of the ports open by the bow of the boat. Now looking at the drawings of Sabine’s boats and measurements from that that are in Chapelle, it is probably a 28-footer. I took plans of her stern, sized it to the official 45-foot width, and added a box that’s 28 feet long, centered on the centerline. One end of it is exactly where the gunport is, matching the photograph. I’m attaching that drawing and an annotated copy of the New London photo. There would be a pivot port behind each of the ports for the aft Parrott to use, giving a very good field of fire even without huge ports.
 
With regards to the 8th July post, that’s a gunport next to the bridge (fifth from the stern, not counting the two stern ports on that side). The gangway was far forward of that, around the main mast, not the mizzen. I believe in that picture there, the platform on the stern is built over the starboard stern chase port. It doesn’t look robust and can probably be taken down as part of clearing for action. It couldn’t be built closer to the centerline, the sweep of the spanker boom gets in the way. The part beneath the spanker is just the bulwark, like any other Brandywine-class ship with a round stern.
 
 

The Naval Heritage website has a bunch of photos of Delaware's figurehead from your link, both the wooden one and the bronze replica they cast (as well as the physical casting of it!).
 
Continuing the discussion of the 1840s sloop sterns, here's St Marys, circa 1874. She's got the spar deck already, but no quarter galleries. Great look at the quarter ports though.
 

 
EDIT: An interesting detail I noticed on St Marys and Portsmouth both, the rudder chains wrap around the stern.

That really only held through the war years. Once peace reigned again, American ships actually became remarkable alike. Paint became standardized with the white stripe (then later extending the stripe over the bow), Any remaining gingerbread was either removed or painted black, with just a few decorative motifs like stars and eagles. You definitely see in the 1820s-1830s there was a standardization through the navy.
 
Probably from Constitution, as you'll notice Boston's is quite different. I think he really kept the same bulwark lines and just turned them into railings. Don't forget that the original six got extensive rebuilds, with different heads. Just compare the depiction of Constitution and President in my comparison, plus Constitution as she is now.
 
Speaking of Constitution and that picture you link, here's one of her old figureheads.

 
And the infamous Andrew Jackson figurehead that replaced Washington.

 
HMS Macedonian's. This was likely the only major piece of the original frigate to appear in the American rebuild.

 
And Ohio's Hercules figurehead displayed on the side of a highway in New York.

 
Some decoration details from Alabama/New Hampshire/Granite State.

That really only held through the war years. Once peace reigned again, American ships actually became remarkable alike. Paint became standardized with the white stripe (then later extending the stripe over the bow), Any remaining gingerbread was either removed or painted black, with just a few decorative motifs like stars and eagles. You definitely see in the 1820s-1830s there was a standardization through the navy.
 
Probably from Constitution, as you'll notice Boston's is quite different. I think he really kept the same bulwark lines and just turned them into railings. Don't forget that the original six got extensive rebuilds, with different heads. Just compare the depiction of Constitution and President in my comparison, plus Constitution as she is now.
 
Speaking of Constitution and that picture you link, here's one of her old figureheads.

 
And the infamous Andrew Jackson figurehead that replaced Washington.

 
HMS Macedonian's. This was likely the only major piece of the original frigate to appear in the American rebuild.

 
And Ohio's Hercules figurehead displayed on the side of a highway in New York.

 
Some decoration details from Alabama/New Hampshire/Granite State.

That really only held through the war years. Once peace reigned again, American ships actually became remarkable alike. Paint became standardized with the white stripe (then later extending the stripe over the bow), Any remaining gingerbread was either removed or painted black, with just a few decorative motifs like stars and eagles. You definitely see in the 1820s-1830s there was a standardization through the navy.
 
Probably from Constitution, as you'll notice Boston's is quite different. I think he really kept the same bulwark lines and just turned them into railings. Don't forget that the original six got extensive rebuilds, with different heads. Just compare the depiction of Constitution and President in my comparison, plus Constitution as she is now.
 
Speaking of Constitution and that picture you link, here's one of her old figureheads.

 
And the infamous Andrew Jackson figurehead that replaced Washington.

 
HMS Macedonian's. This was likely the only major piece of the original frigate to appear in the American rebuild.

 
And Ohio's Hercules figurehead displayed on the side of a highway in New York.

 
Some decoration details from Alabama/New Hampshire/Granite State.

Hi Wayne! Yes you are correct. Standard wasn't really a term at that time but I was thinking more in terms of standard function since those parts by the bow would have been what most frigates required at the time before the bulwarks and railings became solid in later designs. Also though the railings from Philadelphia and New York were reconstructed by Chapelle (after the erroneous reconstructions by Henry Allen) so it's likely he took the railing idea from Constitution (and Boston's plans) as a reference? The bow does look a lot like Constituition I must say. And Talos those are some wonderful looking images there. Is it wrong to say I have a thing for boat butts!

Certainly changed. For instance, the berthed up bulwarks later in the war. I was just struck by how much it was shaped like those two (which were based on anachronistic drawings by probably a junior naval constructor as practice that featured those rail shapes, but as solid bulwarks). Obviously the whole image past the bow is even more simple than the rest.
 
 
Yeah, I know. The last Snow died a few years ago too. I was pointing out that the forum member physically lives next to the old site of the shipyard.
 
And now onto the new stuff. First off, this should raise interesting questions on Portsmouth's stern. It's definitely round, but the quarter galleries are faired in completely.

 
 
Portsmouth's gun deck after the spar deck was added on top (she was built open-topped). Three visible Dahlgrens, a Parrott in the back, and a sailor reading a newspaper. I have been finding some amazing Portsmouth pictures.
 

 
 
Being burned to recover her metal in Governer's Island, New York in 1915.
 

 
On the subject of the gunport windows last page. I think Constellation's constellation windows are even crazier. Also she looks amazingly sleek in her late-19th century guise.

I almost wonder if it got added around 1876 with the US Centenial that year. Lots of patriotic imagery. That's just a total guess on my part though. Notice they also added two smaller star badges on the back of the quarterdeck, which are blank in Skerrett's drawing.
 
@frolick
Her plans depict her without any quarter galleries at all. If they were added on later (such as when she got the spar deck), it might account for her stern being like that. Albany was the only one of that group to be built with a square stern.
 
EDIT: Just to muddle the waters more, her stern looks pretty round to me here.
 

Yeah, no kidding.
 
Unrelated, a nice shot of Portsmouth and Lancaster in ordinary in 1894, giving a good view of the sloop's stern. Big carving!
 

Another interesting photo, this one from the US Navy Heritage and History Command, Sabine's salvaged billethead. http://www.history.navy.mil/our-collections/photography/numerical-list-of-images/nhhc-series/nh-series/USN-901000/USN-901319.html
 

 
And another one of Santee's gundeck, from further aft this time.

 
And Santee's captain's cabin.

 
Santee's gundeck looking aft.

Yeah, they can be really nice. Notice the forward pivot ports are open in the Sabine picture you show there. And yeah, could be very different. Different builders, different times, etc. They did have different bow designs anyway.
In reference back to the quarter gallery thread we had a while ago, I think I see two half-window plugs on the two aft-most windows on the quarter gallery, instead of just the one center one we normally see. Also the three-pane half-windows fitted in some of the gunports that still have cannons in them!
 
EDIT: Cropped the bit of stern out for a better view here. Tweaked the levels a bit too.

Certainly changed. For instance, the berthed up bulwarks later in the war. I was just struck by how much it was shaped like those two (which were based on anachronistic drawings by probably a junior naval constructor as practice that featured those rail shapes, but as solid bulwarks). Obviously the whole image past the bow is even more simple than the rest.
 
 
Yeah, I know. The last Snow died a few years ago too. I was pointing out that the forum member physically lives next to the old site of the shipyard.
 
And now onto the new stuff. First off, this should raise interesting questions on Portsmouth's stern. It's definitely round, but the quarter galleries are faired in completely.

 
 
Portsmouth's gun deck after the spar deck was added on top (she was built open-topped). Three visible Dahlgrens, a Parrott in the back, and a sailor reading a newspaper. I have been finding some amazing Portsmouth pictures.
 

 
 
Being burned to recover her metal in Governer's Island, New York in 1915.
 

 
On the subject of the gunport windows last page. I think Constellation's constellation windows are even crazier. Also she looks amazingly sleek in her late-19th century guise.

That would be the I.L. Snow shipyard in Rockland, Maine where Sam Ladley here lives. Best place to start investigating.

Looking at the plans, the Brandywine-class frigates have a very flat stern with rounded corners. Portsmouth is closer to Constellation. Looking at Germantown again though, with her quarter galleries on, her stern almost looks flat (despite not being so). Explains why she and Portsmouth only have two stern ports and no quarter ports too. The structure of the hull itself looks in between Brandywine and the Hartford style. You can see what I'm talking about with Germantown here.

I almost wonder if it got added around 1876 with the US Centenial that year. Lots of patriotic imagery. That's just a total guess on my part though. Notice they also added two smaller star badges on the back of the quarterdeck, which are blank in Skerrett's drawing.
 
@frolick
Her plans depict her without any quarter galleries at all. If they were added on later (such as when she got the spar deck), it might account for her stern being like that. Albany was the only one of that group to be built with a square stern.
 
EDIT: Just to muddle the waters more, her stern looks pretty round to me here.
 

Yeah, no kidding.
 
Unrelated, a nice shot of Portsmouth and Lancaster in ordinary in 1894, giving a good view of the sloop's stern. Big carving!
 

She was a training ship and not going to go into battle, probably moored for good by the time that was taken, so it's no surprise it's so heavily decorated and furnished.

That would be the I.L. Snow shipyard in Rockland, Maine where Sam Ladley here lives. Best place to start investigating.

Another interesting photo, this one from the US Navy Heritage and History Command, Sabine's salvaged billethead. http://www.history.navy.mil/our-collections/photography/numerical-list-of-images/nhhc-series/nh-series/USN-901000/USN-901319.html
 

 
And another one of Santee's gundeck, from further aft this time.

 
And Santee's captain's cabin.

 
Santee's gundeck looking aft.

I haven't found any yet. Of thse windows, I see three patterns in that picture. The first two on the left have three panes with vertical borders between them and the cannon still filling the port, then one with only two panes and one vertical border. The guns on the other three are removed, maybe turned sideways against the hull, and the window has an almost sunburst pattern to it. They appear to be half-ports too, but the ports on those three windows don't have the cutout on the lower half for the cannon barrel. I can probably draw up some sketches of them if need be. I imagine they were there for those two very reasons too. Those should be the officer cabins, specifically, so it makes sense they would be the ones fitted with windows. Look at the difference in diameter between the cannons on the gun deck and the spar deck. The above are likely 32-pounders, so the bottom are either 8" 63cwt guns or Dahlgrens.
 
You can also see the badge on the quarter gallery and the two half windows on it I was talking about too (the upper two panes on the center and aft windows on the quarter gallery itself)

Yeah, they can be really nice. Notice the forward pivot ports are open in the Sabine picture you show there. And yeah, could be very different. Different builders, different times, etc. They did have different bow designs anyway.
In reference back to the quarter gallery thread we had a while ago, I think I see two half-window plugs on the two aft-most windows on the quarter gallery, instead of just the one center one we normally see. Also the three-pane half-windows fitted in some of the gunports that still have cannons in them!
 
EDIT: Cropped the bit of stern out for a better view here. Tweaked the levels a bit too.

Nice I didn't realize the quality of the images on LOC are so much higher. Looking at the billethead scrolling comparisons on Sabine vs Santee, they are similar but perhaps a bit different. Is it safe to say scroll work was different of every ship of the time or did sister ships have essentially the same scroll design depending on who commissioned the work?

Huh, here's an interesting picture I found poking around LOC. This is Sabine and if you look up the full-size (88mb) TIFF, you can clearly see her aft Parrott sticking out of a slightly wider port out the side of the ship. You can also see the bracing for the forward pivot ports on either side of the (double!) cathead. Notice also the gunport covers hinged at the bottom on the stern windows, as well as the window plugs on the last few broadside gunports on the gun deck.
 

http://www.loc.gov/pictures/resource/cwpb.03820/