I apologize if this info is already out there, but I had a really hard time finding it. So, I figured I would make it easier for the next guy.

The center firewall (bulkhead), cover on my XJR just had this hole, which obviously was supposed to have a clip. After a lot of searching I found the two cheap pieces it was missing. See below:

 

Doug,
Does this plastic fastener actually fasten anything or does it just plug the hole?

 

The gray part is the socket or nut so to speak. The black plastic bolt holds the panel in place.

I had to replace both of mine at one point. The gray clip broke in my case.

 

Exactly.

There is a bracket coming out of the firewall that it connects to, so it doesn't just fill the hole.

 

Just so it's easier to see/read the part #'s. The glare make it looks like KRF10CC01.
KRH100005
KRF100001

 

Take the centerpiece off, slowly; it is easy. You will then see where the grey piece goes and how the black piece holds it in place. Geez!

I found an old license plate bolt in my tool box worked just fine.