If i were a betting man, I'd say they rule like this:
states have the power to ban things, localitys do not unless there is state law saying they do.
Than as Beck pointed out, Chicago would need to ban railroad ties, or have them licensed and registered.
Baseball bats would be next, no longer classified as "sporting goods" but potential lethal weapons. Than shovels, etc,....
SCOTUS needs to put this issue to rest with NO gray area. A definitive ruling, not allowing localities to over regulate a Const. Right.