As for the power brakes, my '72 Super came with manual brakes.I have since changed over to power brakes

. You can always pull the metal trim ring on the headliner and see if there are holes in the roof for the snaps for the ring. I believe (I could be wrong) that cheyennes had the headliner as part of the interior package, and others didn't. If the holes aren't there, it's not a true cheyenne, and the owner added it after the fact.
Someone please correct me if my facts are wrong.
Shawn