Here are some more pictures of gun#2. I could not get any good pictures of the proof marks but this is what was on each barrel flat;

16 than underneath that was 70mm and then under that was the letter N, this occured on both barrels but one barrel had some sort of crest and then the number 942 underneath the crest. My guess is it was made September of 1942. Can anyone help out with a value on this one?