Hello there,
I have owned GMC CCKW 353 open cab as well as a dozen CMP's over the years.
I recall comparing the wood steering wheel of my Chev C60L with that of the GMC - one had a simple centre spider whilst the other also incorporated a rivetted sheetmetal inner spider for reinforcement.
Only trouble is, now years later I just can't recall which vehicle had the reinforcement piece.
I'm pretty sure they were interchangeable as I once loaned my good timber wheel to a fellow collector to move a dead GMC wreck - it fitted straight on so well I never got it back !!!
(I know who you are and where you live by the way...)
Cheers
Phill