Original Rear end type on my 70 Duster

I don’t think that the axle was dependent on the brakes the car was built with. I’ve owned manual front disc cars with 7 1/4” axles. One weird one was a 73 Duster 318-904-7.25 with 2.76 gears. Stripped car, too. No front sway bar, Rubber floor mats, foot pump for windshield washer, no A/C, manual steering. The title stated in capital letters: PRIOR POLICE.
I never found out what that meant.