I don't know. Not that a sequel to a popular game is out of the question, but I'm not totally sold on the 'leak'.
Maybe internally "The first Last of Us" is the retail game and the DLC was the second. Or maybe he just flubbed his words.
But on the other hand, he did seem nervous after he said "The first Last of Us" and the dude on the left sounded like he was trying to help cover it up by moving the conversation to the DLC.