Bornco - Bartamos lays it out above. There is a chance cab was changed. No harm. Some like the high hump. The suburban (you provided as example) may have an entirely different arrangement - I need to research that some more. I had thought in the past, low and high humps could be interchanged with the correct filler panel.
Look at the ID number (VIN) on the plate in cab, carefully match to number on frame rail. Then look at the rivets on the ID number plate in cab. Are those rivets original or do they indicate the plate was removed and reattached.
As far as the carpet - you are squared. Need high hump.
