Bought a new boot, you know, the convertible top cover you snap into place when you're top down. I think that something is missing from my car.The cover presses into a groove on the back of the back seat but this groove thingee is missing. It may have been removed when the seats were redone (one or more owners ago). There are small holes factory drilled in the structure that joins the back of the seat. I need what goes here. What is it called-where can I get one?BC