From looking at google images for "03 Sierra 2500HD", the bottom of the front bumper appears to be at roughly the stock height w.r.t. the center of the front wheel, and the rear of the truck is slightly higher than the front, so I would say it's very close.
2004 GMC Sierra 3500 C&C, added 4WD, 6.0L gas, Extended Cab, SLE, Transgo 4L80e-HD2 kit installed
Whee! Dually Club Member #1109