Same material found on engine cover (seal part #9 from the list Denis posted), mocked-up here. I assume the long sections running the length of the engine compartment (part #18 on this list) are also the same.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.