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
and the model is..................................
.22 cal
Around 1955.
Model number will be inside the crane area when you open the cylinder.
1961-1962
Go to proofhouse.com and take your pick.