I saw a 1959 color, Jade Green Poly (which back in the day had nothignt o do with polyurethane, but was short for polychromatic, anoter term for metallic). That's pretty close to the Speedway green I'm looking for.
Yes, in the US urethanes didn't really hit the street until the 90's. When we restore bikes and try to get a close color, any metallic in the original paint is going to skew the spectrometer at the paint shop and yield an inaccurate hue.
Several MFGR's did produce their own color codes, sometimes from off hand sources, like John Steens' buddy's 32 coupe. Very few of us use rattle can on vintage, collector or more valuable bikes. Some use powder coat, based on whatever codes they can find. Guys like me paint, based on either color codes we dig up based on historical reference as DanFord alluded to. There's nothing wrong with doing all of the mechanical work and rattle canning it and then riding it as far as I am concerned. It just not fuel proof, and it doesn't look, or wear as well.
Competition Orange for example was used by HPE/Muskin and was the Ford color from 1971. Several other hues are used more than others, like Marina Blue. (GM)
I'll use either a single stage, or a two stage, depending on the level of finish I am looking for. It is extremely difficult to color sand a mini bike, so care must be taken when using two stage paints, and flowing the clear.
My last project was a vintage kart done in a three stage candy apple red. Now "that" was available back in the mid sixties, and used, but not like my HOK blend of urethane candy over an extremely brilliant metallic base coat. It was a lacquer which HOK went away from in 1993 or so.
Here is a link to some Rupp Colors that based on their dates and codes, were assembled by fans well after the bikes were out of production. Another way to look at it is if we're going to be using the urethane based coatings, we're already making them more gloss than they ever were. I played around with some oil base, and did shoot some reduced with "thinner" and catalyzed with enamel hardener. It looked fairly old style. End of speech. Here is that link:
WIRING DIAGRAMS & PAINT CODES Like everything else in this hobby, "as long as you're happy."