Understood about your truck being a WWII GMC CCKW. To the best of my knowledge, the '42 has the same basic cab structure as found in commercial '41-'46 GMC and Chevy cabs.
Here's a screenshot from a reported G506 GMC (1st pic) and a non-military 1942 GMC 1-1/2 ton. As far as my eye can tell, the general cab construction is the same, unless I'm missing something? Always interested in learning something new.
