I should have noted it is a '48 Kaiser. Since the body shop removed the seats and replaced the floor pans, I don't know exactly how they were mounted. I don't know if there's supposed to be a fixed threaded"nut" or if a bolt is just supposed to go through with a nut underneath. I also don't know if the '49 would be the same or not. But there is a bracket, I guess you'd call it, on each corner of the seat frame that would indicate that a bolt should go through it.