Randy, As you may know, there are guns out there, and made up "sets," that have barrel w/o any markings on the top rib of any kind. These are unfinished surplus barrels that were sold off as scrap when the factory moved out to it's present location in 1950, from the old location on Stockbridge St. Most of these barrels were in the white and later owners had them polished, blued or nickeled, to make up a "set." You will see them in all calibers.