Yeah, I wouldn't rely too heavily on that car for restoration accuracy; it had to be pre-production, and I think it's the same GTX in the brochure.
Always thought the red AG unit was interesting, but I've only seen it on Dodges; never on an original Plymouth.
Looks like an early-'68 trunk lid inner panel, too.
I've had a few '69 RRs with factory Magnums; the one that had its original spare used a black steel wheel.
The other did as well, but I couldn't swear to their born-with originality, as they had non-OEM tires on them.
My '68 factory-Magnum RR also had a black spare wheel.
I'm sure Chrysler did whatever was cheapest for that.