Yes but hes not ordering a truck and you will find Dana 60 or Dana 80 gears in different trucks. Disc brake size varies depending on year and that weighs in on load capacity.
New or used, if you have an f250 and an f350srw with the same Dana 50 or 60 in the front and the same Dana 80 or Sterling 10.5" in the rear, and the same spring package, the trucks are identical other than the badges and the spring perch block. Compare apples to apples.