I still am thinking homemade...No side doors? I don't see any of the hardware that Sears or the other hardtop suppliers would normally use, and those window sizes are not the usual at all. It is interesting there is such a large back window used when the side window are so small.
Some of those old timers use solid rivets and bucking tools to set them...I have a jeep tub around here that looks like something out of Mad Max due to that method of repairs..Pop rivets didn't really come into general use from what I understand until the 60's, maybe a little earlier. But the quality level acheived by many of the home builders of tops can surprise you. Back then some of the plans in Mechanix Illustrated, etc were just incredible...really complex things. I remember a motorized jeep plan I saw recently that had been published in the 40's...It was a very complicated project requiring a small machine and welding shop, along with woodwork and sheet metal fabbing. When guys didn't have the computer games and TV to keep them busy they accomplished some amazing stuff.