I frame
An N frame .357 Magnum revolver.
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.
A K frame revolver
Yes, a model 66 is a K frame revolver.
1971
K frame.
If you are speaking of a K frame revolver it was 1961.
Six shot, double action, K frame revolver
Yes
Open the cylinder and look inside on the frame where the crane assembly rests.
Open the cylinder and look at the frame that is usually hidden by the crane. The serial number is stamped on the frame.