First off, the ‘37 still used the oval tail lights. ‘37 Cars and later pickups used the rectangular ones you have. Here is a picture of my Carter reproduction and they mount to the stake pocket like you have. If you’re just curious about the original flatbed mounting, I’m no help. I would put a rubber grommet in that frame hole for the wire to run through though.
I have the correct tail lights that will be going on,at the time the truck was put togather I liked the later tail lights better.
