Looks like you have a very nice example of a Model of 1953 22/32 target (Pre Model 35). I can't tell if it is a 4 screw or not. I will est that it was produced between 1955 and 1957. This series was produced from 1953 to 1969 with several engineering changes along the way, including a change from the Improved I Frame to the J frame. Obtain a copy of the Standard Catalog of Smith & Wesson 3rd edition and on pages 118-119 and page 207 will give you the complete history.