Historicaly some rifle or smoothbores had tgs thatwere held by screws, I often womdered if whether there was any engraving on the tg had an influemce on how they were done, I believe that some nose caps on early colonial rifles were also held with a screw, if one carefully reads thru RCA1&2 and Kindigs books there are many little details that we have been told either were or were not done in the past. We have a real problem with judging the guns of the past by those that are being built today at times.