Go to S&W website and request a manual
N
The Model 57/657
100-345 or so
No sn provided.
100-600 USD
smith and Wesson (smith & Wesson) and Sig-Sauer
100-1000 USD
100-400 USD or so
Call S&W and they will tell you.
I can say that the Smith and Wesson model 65-2 was made from 1977-1981.your handgun is included during this 4 year time frame.
Impossible to answer with just the serial number.
The value of a Smith and Wesson model 1026 varies greatly depending on the condition of the handgun. On average, this gun sells for about $500 to about $600 in very good or excellent condition.