What I believe to be the correct frame came early so I took some photos before and after. Wear pattern is perfect with "new" frame. I'm wondering if these were surplussed off without the frames and the wire frames were made up to fill the gap. Could be the early version of frame also. This really got me thinking about how poorly equipped troops must have been in WWII. This rucksack was only for the 10th Mountain Division, not the rest of the Army so all the rest of the army had were those small packs. Sleeping bags didn't come along until late in the war. How did they survive the winters on the line? Blankets and shelter halves I guess.
The tube frame is a lot tighter than the wire frame. Fits much better as the wings are folded in at a sharper angle. I expect the wire frame would catch on all sorts of stuff as it sticks out to the sides.