Some times in the mid/late '00 era GM derated their 3500 drw trucks rawr down to softer rear suspension at 8200 lb range while Dodge/Fords were going into the low 9000-9375 rawr range. Maybe the drw in the pic is one of them.
GM later admitted they made a mistake going soft suspension thinking they could sell more drw trucks to rv folks. Wall street crash in '08 bit GM hard in this size truck sales.
I think in the 2010 ?? era GM fixed that with a higher rawr numbers in the 9250 range.
Now their leading pack with 10500 lb rawr.