I'm pretty sure I saw an official behind the scenes video where they talked to a nokian involved in the design process, and he said they chose to make the white N9 glossy because matte white looked too unimpressive or dull, something of that nature, if my memory serves me correctly that is.
I seriously doubt they would change design so late in a products life cycle anyway, when they're in store it's already very late for that kind of thing. Maybe if they were to pull a Samsung and release a million different versions with the same badge they could.
Saying that I have no doubt that if there's some third party making fascia covers they could go that route though, with the N8 they certainly didn't stick to Nokia's design, though the one I imported from china was really bad plastic, and didn't fit like the real thing.
I'd go genuine if I ever swapped a fascia again, that's for sure.