Here is a very slightly different (and not really significantly different) interpretation:

Vehicle/Unit Serial Number = 8KB059601
8 = Atlanta, GA truck/vehicle assembly plant
KB = 1940 Model Number = Master 85 car
05 = Made in May
9601= 8600th vehicle made in May = 8601th Master 85 car assembled that year (1001 was 1st vehicle, so subtract 1,000 from number on plate)

Truck ID plate stamped with a car Vehicle Unit Serial Number?
or
Plate from a car that was later put on a truck?

Are there other possible interpretations?