As we know that isn't always what ended up in cars.
After 50 years, you expect original
If I was a 67 judge, knew my distributors and carburetors, and saw something I knew was not specified, I would be suspicious. The "book" (read any documentation) may be incorrect, but what is found in a car isn't the best method.
On the other hand, if you come up with something different and
have a source, I'll be grateful for some input and will update the info I've entered.