Thanks everyone.

I'm in Michigan. We have a permanent trailer license that's something
like $300 and you don't have to renew it - but I don't know if that's
a transferable plate, or if a new owner would have to re-register it
if it's sold.

the hitch/wiring. He did not get the truck with a hitch on it.
He had a hitch installed a year ago so he could help his cousin tow a
camper into the woods for deer hunting. So it's not wired at all -
just the hitch.

I'm not sure what all else is included - I think he mentioned a
FishFinder/GPS and marine radio. I don't know if the the boat comes
with a bimini top or a boat cover, etc.

But so far it sounds like, depending on the condition of the trailer
especially, it's probably a bit overpriced and DH should make a lower
offer.