I think you need a different dealer. I bought a new left over 07 255ssi and the rear filler pad was missing. Chapp is sending a new one to me. It is not like they don't have the patterns.
As for how they fit, yes, there are metal bars that go into the indentations like you said. They store in clips on the side of the ski locker on mine.
Call Chapp directly and see if they can help you. Also tell them about that rude dealer. They don't like hearing that info, and will correct the dealer quickly.