Spoke with Ruger this morning and asked when they started inscribing the serial numbers on the face of the Bearcat cylinders. The answer I got was less than useful. The say that 'There is no start or stop time. It depends on how many they were doing in a run." So I still do not know when they started. I could NOT get across to her that they 'started' at some point since none of the older models had the numbers there. I have 93-xxxxx without and 93-xxxxx with, so they sure started somewhere.