Estimated in the mid 60's. Call S&W and they will tell you when it left the factory
The "J" frame is the Smith & Wesson small frame revolver such as the model 36 .38 special. The smallest frame, as in the model 36 Chief's Special.
The model 29 is one.
Yes, a model 66 is a K frame revolver.
I frame
1954.
1955
Around 1955.
.22 cal
and the model is..................................
1) ensure the revolver is unloaded and safe. 2) open the cylinder - Rossi marked their revolver model number on the frame behind the cylinder crane, ie: M31 etc.
Model number will be inside the crane area when you open the cylinder.
Go to proofhouse.com and take your pick.