Back in the 70s, VCCA tech advisor for paint and finishes, Wayne Martin, converted old paint colors to modern (at the time) paint codes. These were published in the G and D as a regular feature as he would complete a year of codes. I used this info to select the Blue for my '35 Standard, it was a '71 Opel color, as I recall.
I don't know if these articles are indexed anywhere, but it would have been in 1975 or early 1976 that I chose my color. My old issues of the magazine are packed away and I don't really know where they are so I'm afraid I can't find the info for you. I did not use Wayne's info to paint my wheels. A friend was painting his wheels yellow and offered to paint mine at the same time so I agreed, knowing they would not be the right color.
What's odd is that I came to this section of the site to ask the same question so I can correct my wheel color. That's when I saw your post. My situation has one more wrinkle. I am in the powder coating business and I want to coat my wheels. When the correct color is identified, I will still have to search for a powder that matches.
I hope someone has some helpful suggestion as to finding those old G and D articles.
Mike