I've called 1-800-MY-APPLE twice and they indicate that they are the default matte systems.
I want to get the 15" 2.4ghz model myself, but really want a glossy screen. The second guy I spoke with took my email and indicated he would contact me when some were available. Not sure if he (and others there) know exactly what is going on. The first guy earlier in the day didn't realize that they posted battery life hours on their website when I asked him about them. (?!?) I wonder what they get paid, I should be working there. I just need a computer with the internet and I can read from the Apple website. 🙂
So anyway, since glossy seems to have been a BTO option, albeit free, it seems unlikely for glossy models to be available on clearance. I've been looking at some resellers, but no specific luck yet, although some do sell previous generation glossy models with various configurations.
Any more sagacious information from others would be cool though...