You can get it lettered by S&W.
You can get a letter from S&W for 50 USD
@ 112 years old
Need to know the caliber in order to answer.
100-500 USD or so
Made @ 1964.
50 yrs old
Requires hands on appraisal
Anywhere from $300 to $550.
Impossible to answer without more information, such as caliber and type of action.
You can get a factory letter for $30 that will give you history. Value will depend on condition, barrel length, caliber, finish, grips, the actual model it is, etc..
Cannot be determined from just the serial number. Need a DETAILED description of ALL markings.
Your Description and serial number indicate that you have a Smith and Wesson model 30,or 31 which was made between 1961-1970.