originally any undercoating was an option, and likely only on the underside of the cab .... haven't seen any documentation about paint on underside of the fenders, but I'd bet they were primer black with some body color overspray around the edges, like the hoods .... a good 'elastic' undercoating helps protect the paint job from star cracks that can be caused by stones thrown from the tires, inner fenders are no protection from that
Bill
