Still kind of rough inside, but thanks so much to David for his generosity in giving this cleaner to me! I don't have a hose yet, but suction at the hose connection seems to be pretty strong.
Nope those red ones from circa 1978 came with power nozzles but the power nozzle cord was external and wrapped around the hose with clips. At least on the one I bought back then did.
Looking back over "the scans" i see at least two Air-Ride models with the Powermatic feature, and both of these have the cord mounted on the hose externally.