Mine is the same except for it's higher on the passenger side. No rust, wrecks. After some investigation. I found my cab wasn't level. Not sure if it is sagging or poor assembly (I think mine was built on Friday.. LOL.
At any rate, I measured the difference between the cab (again asssuming your cab is rust and damage free) and the frame and found the exact difference in my bed height. This resolved another issue that I have with the passenger fender sitting too low on the radiator support.
As another, more experienced fellow board member noted, always start with the cab first then work your way back and forward for correct alignment. With a little work and a good cab and frame, you can get it perfect... for those of us that have a compulsive disorder
