If not a studio prop...about I could tell, is that it is or started Life off as, an Open-Top Percussion Revolver, along the lines of a Colt, but, seeming to have some odd details, maybe a Conversion Cylinder arrangement or Shield over roughly the front half of the Cylinder..?
That area looks larger in diameter than it should for an 1860.
Yet, the Cylinder retaines the nitches of a Percussion...where...a Cartridge Conversion would have eliminated those I would think.
The diameter of the front area of the Cylinder appears to be having it's top higher than the top of the Frame and Barrel are...
...and the Frame in front of the Cylinder, is not quite co-responding to that of the 1860, nor to the prior Flat faceted Front 1851 Navy or Dragoon kinds.
The toward us side - the Revolver's Left side - the Recoil shield seems to have an odd relief, which I do not remember seeing on Colts, which had the relief ( for placing Caps onto the Nipples ) on the other side of the Revolver.
Looks like it has an ejector Rod housing, rather than a Loading Lever.
Lotta weirdness going on with that Revolver...all tolled...
I am kinda thinking it was maybe a slightly naive Studio Prop Chimera.
Or, the original Image, or some image from which this one was taken, suffered some retouching which had confused some of the details of the Revolver.
If it was an Actual functioning Revolver, I would say it has the rebated Percussion Cylinder, but having some differences from a Colt proper.
Maybe a 'Brevet' or European knock-off of something Originally Percussion and Colt-like in design, which was then converted to Metallic Cartridge...which then had a Percussion Cylinder installed...??
Lol...