There are TWO receiver ratings...
The FACTORY INSTALLED hitch is a class IV... 12k with WDH. 12k trailer, but a funky 800# tongue weight (according to the manual)... but I'm not sure that can be correct since a class IV rating is 12k/1200#. I'm not sure about the ratings of the bare hitch.
The DEALER INSTALLED hitch is a class III... 10k with WDH. I believe this is a 5k/500# bare rating.
You can tell these apart by looking at the hitch... if the receiver box is bolted onto the crossmember, it is class III. If the receiver box is welded to the crossmember, it is a factory class IV.
I've been down this road already.
steved