Charlie, That type of forend fastener took the place of the banjo shaped one in the mid 1930's and lasted into the Marlin era. (easier to cut out compared to the banjo shaped one) Less desirable, I wouldn't think so especially a 20 ga. and with ejectors. The one nice thing is that it will have 2 3/4" chambers and should be stamped on the barrels water table I believe.