By the way thanks for the pictures (just looking at them).
My father was in the 463rd BG,772nd BS (different group but in the same wing) and I saw that he had a combat mission on Sept 20,1944 to Szob,Hungary.The target listed was a railroad bridge.
It says no flak in the Pilot's log book.He was piloting B-17 G 44-6377 on a ship named Pretty Baby's Boys.So other 5th Bomb Wing groups must have also been involved too.