Uberti.
I have a Colt Blackpowder Firearms 'Second Series' Walker - parts made by Uberti in the rough, shipped to the Brooklyn factory, fine-finished and assembled there so that they could stamp it 'Samuel Colt New York Address'.
That was, for my revolver, serial #1816, some time in 1982, and it gets shot - a lot - with the usual 50gr of FFFg. If you can find one of these, pay what the seller asks.
Else, like I noted, it has got to be the current Uberti version.
tac