I had hooks welded on the same set-up. I had them put on the corners, if I knew better, I would of had a center hook also. I'll probably have one put on during my 50hr service. If you are up for doing it yourself, be sure to put a reinforcing plate on the side opposite of the hook.
Good idea to bolt, IMHO. I had the dealer weld on some hooks, asumed he'd put on decent-sized ones, and they are so small they're all but useless (and completely useless with my chains). MY bad for not specifying the size, but I'll probably cut them off and bolt some on myself.