Welcome to the Stovebolt Page fishbone!
First of all, the serial number should be all numbers. The first number states the year (1=1951). The second and third digits state the make and the series (94=GMC 1 ton). Fourth and fifth digits tell the body style (33=cab with chassis). The remaining 5 digits identify the particular truck (set it apart from the rest).
As for you tire inflator. Got any pictures, never heard of one from the factory before (let alone with something that looks like it could screw into a spark plug hole).
Good Luck.
