You never really know with movie guns. They put together whatever they want to make the impression of what the gun is supposed to be. The mocked up gun doesn't have to be real and it doesn't need to function. The famous futuristic pistol in the old TV series "The Man From U.N.C.L.E." was really a dolled up P-38. For the movie "The Alamo" dozens of Remington rolling block rifles were fitted with non-functioning imitation lockplates to make them look like flintlocks.

The "Wolfman" gun may be a mix of several guns. In fact, the damascus could be painted and some of that metal might even be plastic.