[joedoh]

the one inside the door was probably added. the one on the firewall is probably the original. these werent VIN numbers in 1946, they were body numbers, usually they were titled by their engine number (flat pad next to distributor) but since people changed engines when they wore out this wasnt very reliable. the numbers you are missing are likely the serial part of the body number, so not much help unless you can find some documentation of the number somewhere.

but if you can read the first number/letters you can tell where it was made and what body series it was. mine is 5AL, which is KC built 1941 3/4 ton. I also have a 5AK and a 5DR, which are KC 41 1/2 ton and KC 46 3/4 ton. the gm heritage site has a great breakdown in the body number decoding. if its a 46 1 ton it will probably be a number+ DS, if its a 1 1/2 or larger it will be a number + P and followed by a letter. sand lightly with some superfine sandpaper and you will probably see something.

sometimes (not always) you can tell a 41 cab from a 46 cab by certain clues, a 41 will almost always have a bolt in rear window frame with rubber, a 46 will be only rubber. but because of the war a lot of things got mixed and matched, my 41 has a lot of 46 parts (rear glass, door lock, turn signal housings) but still 41 stuff too (bakelite knobs on the dash, gas tank) so somewhere in history it got all hodgepodged. I would have bet money it was a 46 and thats how they sold it to me but I found the cowl plate in the muck under the gas tank and its 5AL.