What year is the Six Lug 4x4 Brake Rotor Hub Assembly from????

[A-Daddyo]

I have a 70 4x4 short bed stepside C10 that i bought a couple of months ago on CL. the guy i bought it from sold it to me on a lein sale so he did not have any info on the truck. after replacing the motor i finally got the truck rolling and sure enough i have to replace the rotors and the hub bearings seem shot as well. O'reilly,Napa,etc all say the truck is a 5 lug. mine is a six lug with a one piece assembly containing the hub bearings.... Does anyone know what year this set up came from, or is there a way i can locate part numbers so i can replace these?