Open the cylinder and read the model number and serial number - stamped on the frame hidden under the crane.
Depending on the model, there will be many variables.... barrel length, sights, trigger, hammer, finish, etc.
For starters, you said it was "black".... if so, it has been refinished. The S&W revolvers of that era were offered as blued (which is very dark and shiny), nickle plated, or, on some models, stainless steel.