Hi, Lawman Mike.........welcome to TFF.
You're right about the manufacture date. According to the Standard Catalog of Smith & Wesson, #S254586 was made in 1964 to 1965. Most likely 1965.
Blue Book value:
100% - $400
98% - $375
Add 10% for pinned barrel and recessed cylider
Add $28 for white outline rear sight.