That is a round bobied back action Lifter. Very early gun.
The only thing that looks off to me is the hammer. It is a parker hammer, but the one I can see looks like a later style hammer. Like one from a top action hammer gun, not the type that should be on a back action gun.
The back actions were peppered about within the first couple thousand Serial numbers or so. And there was a good amount of variation in those early years in regards to parts and styling.
image.jpg
Top Gun is back action No. 1500
Second is front action No. 1219
Third is Lifter No. 17,790
Fourth is Top action No. 70,259