when i got my car all the covers were broken...i replaced them all with a slightly different design. ones that i had left over from my 93 bonnie. i think they are more of a rubbery plastic if that makes sense and not as brittle.
don't know the part number, I went to the dealer and bought one when I found one missing shortly after buying it. Afterwords, I happened to look online - and they sell them at some online parts shops in CHROME instead of the black. I wish I would have done that. I've sense lost two more - a tire shop happened to have one when I got my tires balanced last time, and I found one on the curb when I went to a parade - so I have all of them again.