Yea I have to call PR bs too, I'd like to see some numbers, otherwise, according to Steam stats(its the only way to play the game, so their accurate numbers), there's barely 100k people playing at peak time.
I know Steam stats aren't a good way to determine sales, but Call of Duty 4 still has a huge fanbase, and according to Xfire, more time has been spent playing CoD4 than MW2.
So yea, I doubt it sold more, especially with those whole server fiasco.