The original plastics were a slightly off white, but they turn what I call "Old Banana Yellow" with time, even when out of the light. If you look at your vinyl coated metal interior skin you will see what is close to the original white color of the yellowed plastics such as the refrigerator vent and AC cover and some of the early end caps. Somewhere in the mid 70's AS started to use a different plastic on the end caps which did not yellow the same way, so if your end caps are quite white, they are not the same as mine were. The white Tambour doors most all yellowed to some degree, no matter when made.
The only yellow that I know of used on original units was similar to the plastic laminate countertop on my '71 Caravel
. It was (and is) a very light yellow, but not that old banana yellow the plastic and White Tambour ages to.
The photos I posted look very nice, and honestly, the actual interior job looks as good in person as the photos. It is easy to be fooled by photos of re painted interiors, but in this case the Krylon Fusion makes the plastic look literally like new. Just do it carefully, using lots of light coats, don't try to put one heavy one on. If you do you will not be happy at all.
In the later 70's the grim Avocado Green was used extensively on countertops, fabrics, carpets, and even stoves and sinks. The only thing to do with that is to replace it. Now, I am opinionated, I hate that color.