I suspect, since the "premium materials throughout" is so vague, that what we see now for the headliner is the same as base (only different in the glass roof vs non-glass roof aspect). PUP including "throughout" doesn't mean base can't have "some", so I think we're more likely to see the same textile on the headliner in non-PUP, but also in the doors where the alcantara still is (for now?), etc. Plastic dash instead of the "wood pore" (which honestly I'm not a huge fan of, but I would probably prefer over a plastic dash).
In other words, PUP gives you "premium" "everywhere" in the car, where non-PUP doesn't. Doesn't preclude some "premium" in the non-PUP, just not everywhere. Which means they can put base model materials in the PUP as long as they call it "premium", and while they might be stretching the truth awful hard, they might just barely skirt by legally with regards to misleading advertising...
Honestly, if we still get synth suede on the doors and any other touch-heavy areas, I'll put up with the textile headliner, but I won't like it. I do wish it was available in other colors. I'm really not happy about the potential for having to try to clean the textile...