Oh you're not done with just the Come Up winch. You also need the mounting kitv which is $499. Here are the GMC part numbers:
The part numbers may or may not show up at GM accessories web site. Call your dealer and they can call to order them. There is stock floating around so, if you want one, be persistent as the initial response may be that the parts don't exist. I ordered them and they just came in. Dealer installing it next week.
- AEV Winch Mount GM Accessory part # 19434379
- Come Up winch with wiring GM Part # 19434344