IMO, it looks hacked from a conventional, but perforated tray they sold in the '60's. It looks like the ends were cut down and the folding handles added so it could be put into the top of a chest. I doubt the ends would have been left sharp and not hemmed over like the long sides. I have 1 of the trays at home and use it as a tool tote around the house.
The holes in the ends attaching the handles look to be at different distances from the bottom, and I doubt they used what looks like MS/AN type aircraft hardware to attach the handles to the tray.