100-1000 usd
Impossible to answer without more information and what you think "cocking indicator" means.
Until @ 1978
I have a mod 41 ser.# 137xxx and it was made in 1970. it has the cocking indicator. You can call S&W and they will tell you the date of manufacture and it,s free.
Smith and Wesson Model No. 2
The frame size of a Smith and Wesson model 66 is K.
No such model listed in the Standard Catalog of Smith and Wesson. You will need to call the factory.
Smith&Wesson model 14
The smith and wesson model 18-3 was made from 1967-1976.
The Smith and Wesson model 19-5 was made from 1982-1985.
Call S&W and they will tell you when it left the factory. It could have been made a week to a year before. 100-1000 USD
Standard catalog of Smith and Wesson by supica and nahas
The Smith and Wesson model 915 was made from 1992-1994.