My ratings and should be same/similar to that Sub you are looking at
GVWR...........8,600
FGAWR........4,250
RGAWR........6,000
GCWR.........16,000
CURB............5,400 - 6,000
Actual.............7,200...with me (180), toolbox (+200), misc (apprx..50-75)
MTWR......10,000.....meaningless unless that Sub actual weight is 6,000
My door label has been posted, but not at home and using iPad...so search isn't working
(edit...found it)
Here is a typical GMT800 'half ton' Suburban's door label
Here is the 2000 (GMT800) GM GCWR matrix chart