six lug rotor ?

[GMC3]

I know this is an old topic, but couldn't find my answer when I searched. I have a 69 frame with 6 lug rear and a front end off of a 78, can i buy the newer 6 lug rotors for the front, or do I have to have my axles re drilled to the 5 lug? If the 6 lugs rotors will work, what years do I need and do I need any other parts for the conversion? Also, I read something about hub size, and if I buy aftermarket rims, will they fit all the way around my truck

thank you and sorry if this is repetitious