Locking hubs were an option back then and not all trucks were equipped from the factory with locking hubs. Being the truck in the brochure is a 3/4 the hub caps were deeper allowing the actual wheel hub to be covered. On half tons it was different because the hub caps were shallow so even without locking hubs those hubcaps would still need to be cut out. My fathers 62 did not have locking hubs upon delivery so the dealer installed them.