My 68 seats that I am preparing to retro in to my 67 have the spacers on all the studs so I am assuming they came from the factory.
Do you have the weld in support plates around the floor pan holes?
Interesting.. I took the seats I have out of a wrecked 69 Formula S Fastback. Original car , never been apart. Even got the build sheet somewhere. It lost a fight with an 18 wheeler in an intersection running a red light. Maybe the spacers were in earlier models??
