If I'm reading the Standard Catalog of S&W 4th edition correctly, the 19-3 was made from 1967 to 1977. As Quikdraw67 noted, we need the serial number from the bottom of the grip to narrow down the date. You will need to remove the rubber grips to access the SN.
Even though it may not have been fired much, it shows a lot of wear and the does not have the original grips and apparently not the box or paperwork. I don't know how desirable the 6" barrel is or how that affects value. Just a ballpark estimate on my part, maybe $400-$450?