Gary is still a douchebag.
After Ash beats him in the Silver Conferences, Gary announces that he will no longer be a Pokemon trainer, and only be a researcher.
Then later, after Ash returns home from Battle Frontier, Gary's brand new Electivire beats Ash's Pikachu in a friendly match.
Obviously Gary was training the entire time, only telling Ash he wasn't so that Ash would be lulled into a false sense of security. And after Gary wins that match, he announces he'll be going to Sinnoh. So, he's a fucking liar. He still trains.