None have ever popped up.

Has anyone seen the two different chromium promos for the Harley Davidson Lifestyles Collection Album set (Skybox, 1994)?

In the late 90's, Bill DeFranzo was looking for a group of Marilyn Monroe (Private Collection, 1994) prototypes I had never seen before. At the time, I hadn't seen any of the red border ones yet but I've never heard of anyone but him mention silver and gold ones with a silver outside border. I'm assuming he had seen at least one or someone he trusted told him they existed. I still haven't seen one.

I was looking at some of my car-related promos today and remembered that there was a hard-to-find Chevy set prototype. I don't have it but it's a chromium version of the #17 "'29 Series AC Sport Coupe" prototype. PCE2008 says it also has a different back. Bill DeFranzo was looking for it in the late 90's. How rare is that?