It's fairly obvious that a television show like Gossip Girl that targets Generation iPod would use product placement throughout the show.
Like how all the characters text their little hearts out on Verizon phones and the Smart Water placement on a couple episodes.
But an American Eagle button-up on Chuck Bass on episode 2x04? I know AE did the same thing with The OC in its prime, but idk...Gossip Girl isn't the OC. It just doesn't seem appropriate. Chuck Bass isn't one to be frugal.