We will never know the real appearance of any 50-60 year old color.
Color photographs from the 50s, original paint chips from the 50s, illustrations from the 50s,
and copies of any of the above are distorted. The pigments used in formulas are either non-existent and/or they are simply not provable to be the same as whatever was original. Even a well-protected color sample/chip has most likely changed at least a little from its original appearance.
Usually you can find a protected area on a vehicle, such that you can tell if you have a particular color-name: in 1954, for example, you should be able to distinguish between Ocean Green vs Transport Blue vs one of the two Mariner Blue - they seem to be distinctly different colors.
The best we can do is to try to come close to the renditions of the colors we now have facsimiles of. This allows us to make good speculation, and interesting findings from detective work, but we will never know how close to an original color we get with a modern color/paint.
