I think you might be onto something Duff. My memory not being what it used to I can't say definitively but I seem to remember red lines being the standard tire on the 400 sport and ho option cars so maybe the deluxe wheel discs were the lowest option wheel cover with that package instead of the normal base hub cap. As far as what you see on your phs meaning that the deluxe wheel disc were available as an option on those cars without the custom trim package I don't think that is plausible because they were available to all the cars with the hub and lug centric standard wheels. But again my memory and deduction skills have been greatly diminished since my strokes so take this all with a grain of salt or sugar which ever works best for you. When I get some time I will go through my materials and see if I can confirm