Is there a possibility that GMC offered parts and/or accessories for dealers to use when a fleet/commercial/government customer submitted a bid with specifications that required a 12v system?
I ask this because the 1955 GMC Sales brochure makes specific reference to providing new RPOs to meet 12v bid-specifications, especially for school buses and larger trucks. Having RPOs instead of parts/accessories would make life easier for a GMC dealer. Just a guess.
