am guessing a Model One and One-Half 2nd Issue. Five shot cylinder, .32 rimfire, around 100,000 made right after the Civil War. Worth around $300 in that condition assuming it works and isn't rusted out or anything.
Possibly a Model Two Old Army, but the barrel looks like a 4" barrel to me. Easy way to tell is if it has a five or six shot cylinder. Number two is maybe worth $400 in that condition. But I think it's the other one. If you ever do see a Model 2 with a 4" barrel those are worth some bueno dolares.