Yes I have factory CF on my XJR. All 4 doors trim panels, the dash panel and my hood vents are CF as well as my engine cover. There were different levels of CF. Most cars just got it on the interior. It was available on more than just the X575 but it was an expensive option. My window sticker shows the CF package at $1575 option code VPFA.

Those black squares are just pieces of rubber? They are just glued on so yes they could fall off and be the source of your rattle. It's very easy to replace them with any square piece of rubber. The veneer has not separated and I think the panel is installed wrong? Did you look at my post at the beginning of this thread? You don't have the "C" hooks from the trim panel engaged into the door panel.

Here is your picture and I have circled the "C" tabs in green that MUST be engaged. Remember this panel is a bit different. First you engage the "C" tabs. Then push the panel forward towards the front of the car. Now all the "C" tabs are engaged properly and the trim panel is held tight against the door card. Finally you need to push straight in on the panel to engage the two clips I posted up thread. Again these clips are plastic and most likely have some damage and should be replaced to prevent rattles.




Here are the "C" connectors (That I circled on your picture above) that need to be fully engaged before the panel is pushed forward.



Here is a full view of the backside of the trim panel. Note all 5 "C" connectors MUST be engaged BEFORE you install the 2 retaining clips.





You need to remove the trim panel and read my post up thread again so you understand how those panels are attached. If there is any gap you have them installed wrong?

The round items you circled are part of the casting and are there to space the trim panel off the door card and to keep it from rattling after it's installed. There are no rivets involved. This is the area I covered in noise mat when I upgraded all 4 door speakers and applied sound deadening pads.

What's most likely happened is that trim panel was removed and installed incorrectly. Then they lost some of the rubber bumpers that keep the panel tight against the door card. When they re-installed it they did not engage all the "C" clips. This left a gap you found and caused the rattle you heard.
This should be a simple fix and does not require adding anything.
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Just to clarify, the picture of the backside of the veneer is the same picture that's posted at the beginning this thread. It's not my actual veneer. I just used it as a reference. To my knowledge, my veneer has never been removed or reinstalled. My car just started making the rattling noise this past summer and I've had the car since 2019. The front side red square I outlined is the source of the noise. There is a long gap at the bottom of the veneer which I could put my fingertips in (before the foam was put in). The green circle area you outlined is solid on my end. The veneer has not technically separated from the door panel but with rubber pieces being worn, it creates the feeling of a gap being there to the touch.

 

Again IF you have a gap the trim panel is NOT installed correctly. You need to remove it and re-install it.

The rubber does not wear? It's does not move? Whether you know if the panel has been removed or not it needs to be removed now and inspected.
No it's not installed correctly and the gap is telling you that. You don't have any idea if the green item circled are engaged. What you have done is put the panel in a bind with that repair. It might work for a while but since that's not your problem you can be sure it will eventually loosen up again.
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