No, he started to sign balls as quickly as he could, but, if you look at the footage, you see the staff official points him to sign the camera and he left... there are other matches on schedule and they cannot afford players to stay more than the time of an interview and two or three autographs.
If there's a player who signed many stuff, it's Federer. He's known for that amongst his fan base... but, you know, he can't just sign things; if he did, he would no longer be able to play tennis.