Rear Brake Rotor Question

[Annihilator]

Hi guys, I am researching good quality rotors for my '01 Z71 1500 ext cab. I noticed that under the acdelco brand, it specifies different rear rotors if the vehicle is posi equipped. Mine is not, however I would like to add a posi carrier in the future. Why the different rotors for posi?

Thanks!

[zibzer]

seems strange. I had a posi carrier put in my truck and I continued to use the original rotors..

 

[redvett]

No difference between the two.