It looks like the Model 28 evolved from the Model 21, which was reportedly manufactured from 1920 to 1928. Model 28 production seems to have run from 1927 to 1938. They do look very much like Winchesters until you get a closer look. The tang safety and that metal arm sticking up from the pump mechanism are pretty good clues that it isn't a Model 12. If Winchester had ever written a letter demanding that Savage cease production, it doesn't look like they paid much attention to it as production spanned something like 18-years. They appear to all be 12 gauge as there is no mention of sub-gauge guns. Considering the number of years of production, I've never knowingly seen examples of either model.