Stock tanks were mild steel, painted black. But stainless aftermarket tanks have been available for many years, as have chrome or nickel-plated stockers and even aluminum. Try a magnet- if its magnetic, they're plated stockers, and could be chrome, nickel or cadmium plate. If its not magnetic, then it could literally be anything.
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.