100-500 depending on specifics
With the serial number that you have provided,your Smith & Wesson model 439 was made in the year 1982.The model 439 was a second generation double action 9mm handgun which was made from 1979-1988.
No such item made by S&W
You will have to call S&W and give them the serial number.
The Model 61 was never made in stainless steel. If you are sure it is SS and not Nickel, you will need a professional appraisal. I suggest you contact Roy Jinks at S&W.
Call S&W, want ad, on line auction.
50-350 usd
Varies from 200-500 USD
100-340 or so
You will have to call S&W
If you call S&W, they will tell you when it left the factory.
50-500 USD or so
You will need to call S&W