In New Orleans, you can use anything you want to defend yourself. Hell, two years ago I broke up a fight where one guy was beating the other guy to death with a tire iron. He claimed self-defense in court - and got off. Apparently he carries a tire iron in his pocket for "just in case".
There must've been a background story or there must be other facts to this case which explains how he got off with self defence. Notwithstanding that, anyone can use anything to defend themselves within reason.
Also, a tire iron is a tire iron. It's not a weapon until you use it as such. Technically speaking, no one could stop you from walking around with a baseball bat either.
