By the way, that's the way the rear windows are on mine, except mine have been replaced with louvered sheet metal to ventilate the fumes from the fuel tank. (It was a fuel tanker.)

I would really like to get a better look inside that thing to see if it had the same body mods for a big fuel tank.

Don't lose your head to save a minute,
You need your head, your brains are in it.
Burma-Shave (1947)