trim question on 69 Dart

The kick panel at the bottom of the A post (this is on a 2 door hardtop) is in place. The sill plate is in place. What's NOT in place (cause I ain't got some) is the counterpart to the kick panel that covers the door mating edge on the B post. It runs from the sill plate up to the rear side window slot.

What is it? Rubber or plastic? :shock:

As always, thanks in advance,

Jim