Appears to be the Alcantara synthetic that looks like suede but is MUCH heartier. The C6 first offered this on one of their special editions. When the part price came down I replaced my steering wheel, shift knob, break handle and console cover with the GM parts. Love this stuff. I keep a small brass brush in my console and when I'm stuck in a line, long light or the freeway, I'll give the appropriate part a brushing and dust will fly. The suede feel and look comes right back and never seems to lose any fiber.
Don't know if the SW will only be covered with Alcantara - probably not - or if regular leather will be standard. Given the choice I'd always opt for the Alcantara. Not as hot when you have no choice but to park in the So Cal Summer Sun, grips better than leather, and looks like it wears better than leather. FWIW