open the cylinder, and it should be stamped there along with the serial number
You can not determine the exact model with just a serial number.
Experience, features, reference books.
Check the butt.
1980
No such serial number in Smith and Wesson data.
1974
1980
Call S&W or acquire a copy of the Standard Catalog of Smith and Wesson, 3rd edition
You will have to find a copy of The Standard Catalog of Smith and Wesson and check each model number.
Look on the butt of the revolver.
Read the one on the butt.
Impossible to answer without the serial number.