Using 1998 C2500 For 6 lug Discs

[Lastson03]

Has anyone tried using 1998 C2500 rotors on 73-87 spindle for 6 lug front disc brakes? I was doing a little research and the use the same inner (SET5) and outer (SET3) bearings on a 1.25 inch thick rotor.
The reason I'm asking is, I need a rear differential. I have an original six lug to replace the 1973 5 lug that it is my 68' now I really want to use parts I can go to NAPA and replace if needed and it would be cheaper than buying new 5 lug axles.