1965 Dodge Dart Charger

It's Mylar stretched over (and adhered to) the base plastic.
After searching the Internet I found out that the Mylar was just the thin plastic covering the plastic locking strip.

Er…yes, that's exactly what I said!

You're barking up the wrong tree; the lockstrip was not chromed. The mylar was metallised, something like this. DuPont are an enormous corporation who don't sell in consumer-level (or car enthusiast group-buy) quantities.

As for the texture lines: I don't recall if they were moulded into the lockstrip or were only present in the Mylar layer.

How big would the market for such a product be?

Unfeasibly tiny. :-(