I just bought an (formerly blued) Iver Johnson Arms & Cycle works .38 S&W with a 5" barrel. The owl is looking at the trigger. Under the grips are what I believe "I 644xx" serial numbers with a solid mainspring (see picture). It's a duel post Top Break (see picture) and I believe a second generation model. I believe its a black powder only model but what I really want is the Production Year?