Welcome to the Forum! Are you thinking of buying this gun or do you already own it? According to the Std Catalog of Smith & Wesson (normally referred to as SCSW here on the forum), pinned barrels on the Mod 64 were dropped in 1982. So this gun was produced prior to that year. There don't seem to be any major defects visible so presuming the action is tight and functions correctly, for the sake of discussion we'll say it's in excellent to about new in box (ANIB) condition. The SCSW says such a gun's value is between $285 and $400. There is some discussion about the accuracy of these values. You might want to find a shop or library that has a copy of the lateset edition of The Blue Book of Gun Values to compare. Some members of the forum will add a few $s for guns having a numbered box and appropriate paperwork. Others don't seem to mind so much. As always do your due diligence and check around. Check other local shops and the internet.