I don't know, but I would like to get me one. Anybody???
Yes and no.
As far as I know, Pietta is the only manufacturer of one, but I must explain further and my answer may be a bit convoluted. Please bear with me, sir.
I have always been enamoured with squareback TG's. I bought a new Pietta 1851 Navy repro in 2014 (date code [CM]) with the round/oval TG. I found a source for a squareback TG at Taylor's a few months later, and after them ordering it from Pietta (and then the waiting process considering it was a bulk shipment of pistols and parts that had to clear Customs) I received it a couple of months later. It all worked well, back then.
![](http://i266.photobucket.com/albums/ii274/sourdoughjim/Pietta%201851%20Navy%20Second%20Model_zpswstsu4tl.jpg)
If you are looking for a complete Pietta 1851 Navy squareback TG pistol, you may be out of luck (try GunBroker for used pistols).
Dixie Gun Works used to sell one listed as Dixie Navy Yank-London Model, which is a complete misnomer (product number RH0850) that has/had the squareback TG in their 2015 catalog. You might call them to see if they have one hiding away in the dregs of their stock rooms.
https://www.dixiegunworks.com/product_info.php?products_id=14047Well, I see that Hawg beat me to it.
I do not believe Pietta offers them anymore, and I say that with the following caveat.
2014 was the last year that Pietta manufactured 1851 Navy repros with the "tail" gripframe. From 2015 (date code [CN]) and later, Pietta changed the grip profile on the 1851 Navy type pistols and this particular squareback TG that I acquired will not work with the newer models.
A comparison:
![](http://i266.photobucket.com/albums/ii274/sourdoughjim/1851_GampG%20008_zps8srvxzph.jpg)
At any rate, good luck!
Jim