Based on the experience of other owners prior to you, 45-year-old paint codes for a paint formula that used components no longer produced are just about worthless even if you can find the correct code.
And if you were able to get a perfect match to the original paint code, the 45-year-old paint on your car no longer has the same tone as the original paint.
IMHO, getting a quality shop or a paint supplier to take a reading of your current paint and then mixing samples to match will be easier and provide a better product than spending time chasing down old paint codes.
Larry