You have my curiosity up! Your front bench seat is not original to your car. The back seat is. I have never seen a bench seat 1970 GT before, and since the front seat isn't original, I wonder if yours was originally a bucket seat car. There is an easy way to tell. Bench seat cars come with holes drilled in the floor for the four bench seat studs. Bucket seat cars have 8 holes - four for each of the bucket seat's studs, and then the bench seat holes have a rubber plug in them. All the floor pans are the same with holes where the bench seat goes and dimples that they drill out in assembly, when buckets are specified. I bet your car has 8 bucket holes in the floor pan and didn't come with bench seats. I'll hunt up a picture so you know where to look. If you had the carpet up there would be four bucket seat reinforcement plates welded to the floor.