Alright, first of all, the article in GQ was probably written 3-4 months ago. Most magazines have a 3-4 month lead time between when articles are submitted and when they actually appear in the magazine.
Second, in another thread, either on rpg.net or on here somewhere, someone mentions an article where Vin talks about DnD. He states that he used to play years ago when he was a bouncer in a NYC club. This was back in like 92-93 when he was bouncing. In the article he laments the fact that he didn't have the time to playt any more.
To explain the $800 spending spree, flash forward to when the interview for GQ was conducted. Vin decides he's going to make some time to play again, after years of not playing. He goes to the WotC store and because he hasn't played in years he sees that DnD 3E is available. He buys the three core books, plus all the splat books (Sword and Fist, etc.), All the other non-core hardcovers and maybe even all the available FR setting books for 3E. Just for these alone you're talking about spending close to $400 or more. Then, because he just made $10,000,000 dollars for xXx he buys all the people he's planning on gaming with, including his DM\writer friend each a set of core books. There's your $800 bucks.
Is this plausible? I think it is. I stopped playing DnD in 1988 I entered high school. I just started playing again last month. I went out and bought the three core rules books.
Also, the idea of him pandering to gamers is laughable. We are too small a group to pander to. In fact, admitting to playing DnD would be more likely to hurt his image, not improve it. Basically, he's admitted to being a bit of a geek. Something that would be more likely to hurt his tough-guy image with the Fast and the Furious Fanboys.