Look at your VIN. The G is rated for a 9000 lbs GVW brake, the H for a 10000 lbs GVW brake. It is the 4th didget of the VIN. This info can be asked at any Chevy or GM dealer if they are willing to help and have the required competence.
By the way, the rear brake is identical, even the automatic load sensing valve is the same. The difference in brake performance is due to the different spring rating of the rear axle and the related adjustment.
Wolf