You might also want to look at the photos section on the Lefever Forum website. Lots of good information and pics of both original and correctly (and some not so correctly) restored guns there. The I grades I've seen seem to all have small block letters on the sideplates. Some DS grades use larger letters, and a later DS grade I have has cocking indicators, Damascus barrels, and the LAC monogram buttplate, all characteristics usually not found on the DS. I have not seen any that have no grade stamp at all, but I understand that there were special order guns, usually of higher grade, that were not grade stamped.