They do not use a "paint chip" they really are for you. There is a weighted recipe/formula for colors, primes, toners etc that create the color. If they do not have the formula many have a camera "Prophet" that with a good clean sample, inside trunk etc "larger than a chip" will break down the paint composition and give them a close formula.
I don't think there is an exacting science when having paint mixed which is why we normally do blending.
But yes, having whatever paint color/mixing info there is to recreate the '64 Ivory color without just guessing from a decades old paint chip, would be very helpful.