Very interesting KKW22Cal
JGA is rare, only about 4,000 made based on S/N study. BiO has one of the cooler one's I've seen.
My rifle S/N 8734 has Commercial N proofs with only the last digit of the serial number (4) on the underside of the safety. No other marks are on the bolt. Pictures make condition look worse than it is.
Simpson states that S/N 8738 is the lowest S/N observed where Anschutz changed the rollmark by removing Thuringen--see page 121. My rifle is 4 numbers below his. Interestingly S/N 8738 has the .22 long rifle. under the barrel S/N, while mine is to the top left. The next lowest recorded S/N is 8686 which has Thuringen below the JGA. It seems that Anschutz was all over the place with their serializing, or lack-there-of and other stamp placements.