A couple of points:
-The cushion must really read "US Air Corps" and not "US Air Force" if for no other reason all pre-"G" models were gone by 1947.
-If you look at the Champaign Lady thread, their new seat cushions also read "US Air Corps"...and they swear it's correct for their late "G". When I suggested here that it was incorrect, I was soundly voted down by members saying that the items were probably ordered before the USAAC was renamed. I disagree, in 1941 the USAAC would have had no way of knowing it would purchase so many B-17s so it clearly would not have placed orders for 13,000 sets of them. My guess is the contractor never bothered to change the marking stencil to read USAAF. The USAAF contracting official who accepted the goods either didn't care, was too busy to made a minor change to the contract to update the name or (my favorite tongue in cheek theory based on no proof whatsoever) was given a few bucks or a bottle of booze to look the other way so the contractor could save a few bucks by not making new stencils.
-As previously mentioned, many "F" models had twin guns in the nose piece, but few I've seen, seem to be as articulated or moveable as the ones shown here.
-What's up with the man posing with the guns in the top photo wearing a beret? I'm no uniform expert but the uniform looks more UK to me...note the shoulder epaulets and the was the top button of the shirt is fastened without a tie. Perhaps a shot of UK forces doing a visit to an American base?