There are two original percussion southern rifles at the little museum near the old mill at Norris dam (in Tennessee). One has a sideplate that looks like a comet. The other does not still have the sideplate, but the inlet is still clear, another comet. I have never seen this before, but there seem to be quite a few that do not appear like we expect. This is one reason I love them. If I get back up there, I will take some photos. These two rifles are out w here one can handle them.