The first M1911 magazines were completely tempered before being blued. The following blueing was taking some of the temper out of the top of the magazine, so to fix the problem, they began tempering the top portion by dipping it into the tempering solution after the blueing. This began the " two-tone" magazine and was used through WW11. During wartime the magazine had a lanyard loop. There are copies out there that work, although they are not original. All Colt manufactured M1911 and M1911A1 magazines had a " . " dot like ".45 " stamped on it.