Impossible to answer, no sn provided.
Call Smith and Wesson and they will tell you. You will be in the early 80's time frame.
Your early J frame model 36 Smith and Wesson was made in the year 1955 with the serial number that you have provided.
The smith and Wesson model 10 has the K service frame.
The frame size of a Smith and Wesson model 66 is K.
The frame.
The Smith and Wesson K frame revolvers were made from 1946-1983.
It is a K-frame.
Next smallest to the X frame.
No, it is an L frame.
K frame
Standard Catalog of Smith and Wesson Firearms by Supica and Nahas History of Smith and Wesson by Jinks.
Medium