Serial Number on the butt.
Call S&W and they will tell you.
Smith and Wesson will tell you if you call them
what is the model
S&W will tell you if you call them
Call S&W and they will tell you.
S&W will tell you if you call them.
Call S&W and they will tell you.
S&W will tell you if you call them
Call S&W and they will tell you.
Impossible to tell with just the serial number.
Give S&W a call and they will tell you.
Call S&W and they will tell you when it left the factory.