This is great information, thanks to those who replied. Typing now, I think I would have constructed my question a bit differently, and would have picked a better sample set of images.
Anyway, I have a Kirkham 427 that I'm about to sell. I'm interested in building a replica 289 Cobra next. While researching, I've become a bit fascinated by the earlier cars, and which colors they might have been painted, where they might have been painted, etc.
Thank you B.P.Bird for the specifics about the BSI color codes, and rr64 I appreciate your illustration of the many variables in that era which cloud the definition of an "original" color on these cars.
So if narrowed down to two general scenarios:
Worker at AC Cars in 1962: "We're going to paint this one red."
AC4 Ruby Red 6192M
AC7 Sunset Red FG40
AC8 Cherry Red/Rosso Chiaro FG39
Maybe a '50s Ace color?
Maybe a British standard red, possibly shared color with other car makers?
Worker at US dealership in 1962: "We're going to paint this one red." My guesses:
M1515 1962 Ford Rangoon Red
M1232 1961 Ford Monte Carlo Red (there would still be cars on the dealer lot in this color in 11/1962)
M0175 1959 Ford Torch Red
M0530 Ford Fleet Red
Or whichever GM color the customer liked
CSX 2034 was auctioned as "unrestored", but was also "sent to Tasca for completion", so who knows? I do like this color though.