Buying a new Chrysler van, and the salesman was tauting a new "alloy"
that he said Daimler developed. He called it an alloy, but the
description seems to indicate a laminate, plastic on steel. I am
assuming it is a single layer of each. He said it provides both
corrosion resistance and sound deadening.

I have never heard of such a material, though I know that they have
been putting a plastic, adhesive backed film on lower external panels
for some time. That is not new. Is there something really new now?