Okay I hate to be the guy who post a question and someone looks it up in five minutes and says, "here you go since you are too lazy to look it up yourself." However i can not find much solid info anywhere. I was thinking someone on here may know more about these than I do and be able to help me out. I thought I had a Stevens Arms Company model G20-A 16 gauge pump, but after reading info on line it is most likely a Model 620-A. I read that there is a circle stamped on the back of the trigger guard with letter stamped in the circle A=1949 B=1950 and so on. There is a D stamped on the back of the trigger guard but there is no circle around it. I guess it could be a circle but then there is no letter stamped inside of it. Any help would be much appreciated.