The question can't be answered until you provide whether it is a rifle, handgun or shotgun. You must also provide the caliber or gauge and all markings on the weapon.
a serial number for a model 29 sw is 72-486
1962
1961/62
@1958
The question can't be answered unless you provide the name of the maker. Even then, the data may not exist.
1972
Impossible to answer.
The "Standard Catalog of Smith and Wesson" by Jim Supica
@ 1959
100-400 USD
1970
s26658