Yes, they would.
You said... “If the kid ate his PB&J sandwich in such a manner that it looked like a gun would the school administration go nuts?”
Ya know, I think you are on to something here. The parents should get in touch with the parents of all the kids in his class, and ask them all to cut a sandwich into the shape of a gun for each kids lunch on a certain day.
What would the school administrators do? Since the sandwiches would clearly be in violation of their zero tolerance rules, would they enforce their rules, ignore their rules, or re-write their rules? I would love to see how that would play out!