[Response to above]: This is not a goof, Beavis and Butt-Head deliberately did that. We don't see them actually change the letters, but it's pretty obvious from what you see on the drive thru menu.
Mr. Anderson: Excuse me, but you y'all call this a restaurant? I drived up to the window to order my large fries, pie and a large coffee just like every Thursday afternoon before I go to the foot doctor, and I'm waiting out there twenty minutes. Hey, you look kind of familiar. You ain't the kids that spray painted my dog last week, are you?
Butt-head: That was uh, other kids.