Originally Posted by
Lascauxcaveman
I don't think it's a copper plating over chrome or vice versa, since you dip the entire frame when you do a plating, and won't see, for example, a chrome chain stay on a copper plated bike.
I was going to say as much on his thread, and got as close as I cared to before getting in an argument, then bailed out. Decided it wasn't worth it.
There probably were some copper plated bikes in that lineup, but by the late 70's I'd bet they had moved to tinted clear coatings.