Look in the Ames catalouge. They show pretty good illustrations and do a good job at explaining which one is which. When you get the sos on incorrect orders, there is a point in which they need to quit blaming the customer and take some personal responsiblity in guiding the customer to the correct selection.
What you describe is roof-rail weatherstrip holder. Use dum-dum (strip caulk) between the holder and the body. CO NOT use weatherstrip glue on the weatherstrip. FIY NEVER use glue on weatherstrip on the fgf coupe. In fact, if you use glue on the trunk strip, it will likely make it leak, and you can rest assured that it will make it rust.