Here from personal experience.
You don't want to use the POR-15 for a finish coat on the wheels. POR-15 IS NOT UV resistant and after a short time the finish will break down to a flat finish that you will be able to rub or wash off. If you do POR-15 the wheels they should be prepped and painted over. Original wheel color for monotone paint was gloss black although I, like Stuart, prefer the satin finish. All this being said you may want to consider powder coating the wheels. As for the hubcaps, if you are striving for original, body color will determine the hubcap and other trim piece color. White hubcaps were only found on white trucks. All other body colors used what in 1959 was called Bombay Ivory. The 1958 color escapes me at the moment but was a similar color. Trim pieces painted would besides the hubcap include the bumpers, grill, and headlight bezels. There would be some difference from what is stated here if the truck has the two tone paint scheme.
