Mike, I would weigh your rig. I think it might be a little more # , if you still have the NL .
If the GM is a 2002, I would look at the possibility of a new hitch . The older OEM GM's were not all that strong and might be a little rusted by now. My OEM had some stress cracks , so I changed it .
I have a GMC 04' and I had to install a Curt 2.5" with an extension that allows the use of regular 2" hardware.
If you need one, here is one option that I used :
Curt 2.5" recvr. this is the extension with reducer. I cut mine down to the right length.
http://www.etrailer.com/Hitch-Accessories/Draw-Tite/RP45292.htmlMy Cargo pro is about 1200# dry incl. my finished interior cargo racks, carrying about 800# of camping/fishing gear.