You may be have looking at a 1500, or a 2500 with the 2" body lift that your truck has. Your truck has the 2" body lift, as you have the 2" black spacer between your bump and grill. If the grill is right up against the bumper, then it doesn't have the 2" body lift (for GM vehicles, I believe Chevy's do it differently).
2004 GMC Sierra 3500 C&C, added 4WD, 6.0L gas, Extended Cab, SLE, Transgo 4L80e-HD2 kit installed
Whee! Dually Club Member #1109