NVH Cover
I have been in the automotive acoustics business for 25 years.
15 years ago we were prototyping barrier/absorber noise covers for oil pans, transmission hsgs, valve covers, fuel rails, intake manifolds etc.
Several of which made it to production for Ford 4. 6 and 5. 4 motors, but were also one of the first things to get eliminated with a cost reduction or "decontent" during late model years.
My guess would be if the pan is soft and flexible (havent even looked at mine yet, nor changed my sig to my new rig 2 days old) it is an acoustic NVH cover, over the metal or plastic pan.
If it is hard and structural like a Nylon type plastic, then it is a plastic pan.
Gotta crawl under this thing and check out more than the mombo drive shaft.
I will stop now.