Jim, yes it's a kind of "flexible spring clip" that's put on (from the inside) before you've stuck the lock cylinder through the hole (it's square and open inside to go all the way around the escutchon). The part number is 213223 and it's called a Lock Cylinder Escutchon Retainer. Its a wierd looking rascal so you need to find an original (i.e. they don't have it at Wally World).
I don't have one but Terry Zeug lists 2 used ones on the last list I have of his. Before you buy one though, see if you can look in toward the bottom of the trunk lid or slip one of those small magnetic extenders in there to see if there's any chance the previous owner dropped it inside the trunk lid when pulling it out. I've done it myself and it can be challenging to fish out.
Hope this helps...Mike
