It'll almost certainly be a bolt-on.
However, U Haul can be a pretty expensive place to by a trailer hitch.
Which brings up my question.
Do you want a trailer hitch, or a receiver?
I've seen more than a few factory receivers on eBay going for around $85.00.
What I haven't seen is the wiring harness being sold anywhere used, which I find surprising since it's so easy to remove...
If you get a class III receiver, you can put one of those way kewl covers on there that look like a little boat propeller and spin as you are driving down the road.