Otto,
If I remember correctly, you are a machinist and have a pretty good idea what a reciever would look like if the markings were removed.On the other hand, a TP grinder does a pretty good job.It just seems that if it never had the reciever ring markings, it wouldn't have the GEW98 either. It's not likely that proof marks would be under the rear sight, since they had to be visible.If the conversion was done for the Gvt., it wouldn't need commercial proof marks.As I stated on the other Forum, I think the 5 is a new serial number.As usual, I could be wrong.
Mike
