They changed roof racks part way through the 1972 Model year, so either style would be "correct".
Any 1969-73 C body roof rack will go on the car, though I'm not sure if the holes are in the same spots for both styles. If you have a rackless car now and have to drill holes, then it doesn't matter.
There probably is a part number for an accessory, dealer-installed roof rack, but I doubt there are any NOS ones out there. The factory installed items will have a separate part number for each piece.
Jeff