So yeah its wrong, it goes on the red part of the bumper and the two screws into the lower. The 4 dimples in the holder should line up with the dimples in the black plastic where he forced those two screws through, and the other two a bit wider will line up with dimples in the red. They are...
It the flap is part of the trim piece, it could also share the color like the carbon fiber look. Could also sell versions of the cover itself that just matches those options, as it is, it kinda sticks out on its own.
What about molding this together with the center console piece https://www.amazon.com/Maxzina-Decoration-Compatible-Conditioner-Accessories/dp/B0DHZSRJ1S I think it would look better to share colors with that and would have a more sturdy mounting this way.
Haven't done this myself yet, still can't decide on a cover, but https://www.amazon.com/dp/B0BWV7HJMZ? https://www.mavericktruckclub.com/forum/threads/detailed-look-at-25-tailgate-seals-adding-about-95-protection-from-the-elements.29911/
Call up another dealer, bound to be one that knows what they're doing. I want to say the other rattle possibility are the pins used to align the windshield.