Welcome to the Forum! Condolences on the loss of your Dad. As others have already informed you, you've inherited a late 1950s .38 M&P, originally nickel plated ("N") with 4" barrel. There were literally millions of M&P manufactured by S&W over many decades, so they are not rare or particularly valuable. Your revolver has been refinished (nickel or chrome?), and it's wearing some nice aftermarket vintage stag stocks. I don't believe it was a S&W factory re-nickel because the hammer and trigger have been plated (which S&W did not do), and S&W would usually stamp a rework date on the left grip frame (e.g. "R 1/62") when they did the work. In its present condition, I think value (with the stag stocks) would be about $600...but you have a nice family heirloom that should be a fun .38 Special shooter. Enjoy!