Sorry been kind of busy, parents left Monday after visiting and my son left today for Arizona for college. Starting to go through some manuals now. Found a picture of the rear armor plate aft of the turrets in a B-25C/D instruction manual. First picture is from a 42 manual and the second from a 44 manual. Pictures 3 and 4 are from the 44 manual. Interesting that the Navigator picture for number 3 shows a movable armor plate