I don't know the material but I have borrowed my friend Johans trunk mat so that you can get an idea. I'll shoot a picture and post it later tonight.
I found an nos clips that holds the transmission cooler lines together so they don't rattle. This is the location for the clips.
When I stopped by Johan today I was able to find out that there is clips holding the trunk lid wiring harness to the left hinge! I didn't know that but this is the way it looked. When I got home I was fortunate to find two of those clips. But the question remain, how many clips was on the hinge?