Ha Ha! Yes, I have been told of the event of the ACCA judging of the 51 Frazer with the V8. You know, I had not thought about it until just now if it was a Dale Hammon engine swap.
I believe it was PPG that first had the visible range spectrometer (hand held color analyzer gun for non-science types) as an aid to match car paint. Well that isn't a cure-all because it first needs to test a non-faded color panel such as the inside of a fender, inside of a glove box door or, on 51-53 Kaisers, the back side of the instrument cluster. Then you have the problem of the mixing components.
I have an interest in the color Carribean Coral, well, because I have a car that color and I think it was a standout color as compared to what the other American car companies were offering at the time. BUT- the 49-50 version isn't the same as the 51 version and any version tended to bleach out with exposure to the sun. I thought the package tray on my car was matte silver or Grey, but in fact, it was body color and the sun had bleached out all the red pigment and metallic component. The paint chip sheets I looked at either were not that correct originally (you could tell your car was Carribean Coral rather than Cardinal, but not much else) or chips had degraded. I suspect it was both.
You could not get Carribean Coral mixed at your local car parts store back in the 1950's because that color (and several other KF colors) were listed as "factory pack." What that indicated was that if you wanted that paint, it would be suppled by the paint company directly. The color mixing components were not supplied to the local stores. The reasons suggested where 1) the proportions needed to get an acceptable match were more exact than what could be expected from a local store and 2) the shelf life was shorter than normal for some of the mixing components.
So, unless a paint company retained its secret formula for Carribean Coral AND they still have all the mixing colors available, what they offer would be a best guess. I solved the problem of selecting paint for my car by looking at cars on the road for about 2 years until I found an suitable match. I won't say it is an absolute match (I think even the factory would have had a problem there) but I do think it is better than some attempts at matching that color.
BTW, the last I heard a well known old car parts vendor was still (after more than 25 years) selling Apple Green paint as the correct color for 51-55 Kaiser engines despite numerous attempts by unhappy customers to correct this mistake.