If it's really a '70s bike, the only models I'd be interested are the Tour de France and Super Corsa. They're both 531 frames. The Super Corsa normally had Campy dropouts and the TdF had Simplex. There was a lot of substitution. My TdF came from the factory with Simplex rear and Campy front. The next model down is the Interclub, and it was made with no-name tubing.