Very interesting discussion. I have always believed that the witness mark on the barrel and the frame were stamped with one blow. After reading all the intellectual comments, I just had to check the witness marks on my Krieghoffs and I found a little kicker. My 1936 and my P-code had a witness mark on the frame only (nothing on the barrel of either). My 1937 and my 1943 did not have witness marks at all. So mhy would there be a witness mark on the frame side only? If it makes a difference, the rejection star on my P-code is on the receiver.
Big Norm