That single stud serves both purposes - passenger seat and riders seat hold down. It is a mustang supplied system different from the oem seat system.That is what I thought but after further inspection that stud (with the bolt hex on the base) is nothing but a stud for the rear seat to hook into. It doesn't even go into the fender at all. I can see two bolts that appear to be holding the seat on but short of finding some way to get between the tire and the under side of the fender I can't see any way to get to these two bolts! LOL! Hence the feeling like a idiot!