I have never seen one in use, have seen a few stowed quit a few years ago this is why the the roof is not flat but the cat walk design. the A-frame was not necessarily used to raise the rear flap but to supply a second lifting point to to get things in the truck to be worked on, in vn, our shop had a few 39 series exspando trucks, I understand the A-frame was a pain in the A to use, HEAVY and AWKWARD to set up/take down, the need to climb on the roof, and you HAD to have the chain fall on the end of the A-frame BEFORE it was erected, I believe this is the reason that you do not see them on 944s and the 809 series