What brand, years, models of trucks?
No roof-racks with wooden slats were available from GM for 47-55 Chevrolet Suburbans. GMC offered a wider variety of options/accessories that were often different from Chevrolet - maybe someone knows about GMC.
Chevrolet station wagons might have had such racks available; and, after-market conversion companies might have had such roof racks as options.
