It may have been an option. My first ex had a 75 MontrCarlo that she got from the original little old lady owner. The original spare had never been out of the trunk and it was not a rally wheel like the ones on the car.
Some of the late 60s came with those 1st generation "space saver" spares, that had an inflation cylinders with them. What a pile those were, but are rare today. If you ordered ralley wheels and didn't want the space saver, you got a bare ralley wheel (no caps, rings)