Suburban at the auction

[RobA]

I went to an auction last weekend to bid on a 71 Chev Surburban. The auctioneer kept saying how rare it was with 3 doors and a "longhorn frame". It was in pretty decent shape with not much rust on it. The interior was nice too, but the third seat was missing. It had A/C but not in the dash, there was a big unit on the roof with vents over each seat. It was factory, listed on the option sheet and the knobs matched the dash. Never seen one of these before, anyone know anything about them?