McGrath Hamin Rolled Gold Plated Mens Ring 10K RGP ->M-H<- Vintage 50s Size 8

McGrath-Hamin men's rolled gold plated ring size 8, stamped 10K RGP. Gold in color, over silver tone metal. I think it's base metal is sterling silver, based on the jeweler's history, but it hasn't been tested. Maker's mark looks like an M and H with two arrows pointed inward. ->M-H<- .Vintage jewelry, circa 1950s, from Rhode Island. Moderate wear, most notable is a dark line at the back of ring (looks like it had been re-sized).