We also have to remember that, while the models may have looked a certain way onscreen under controlled lighting, some of them looked vastly different in person. I was personally shocked to see that the original TNG S1 Romulan Warbird miniature was damn near gray, with just a faint hint of green. The oversaturated green color we all saw on sceen was done either with gels over studio lighting or via color adjustment in post. It is entirely possible that some of these colors may be closer to what they were originally supposed to be than what we actually saw. I can personally attest that model builders mull over this question all the time when it comes to painting their creations. The fact that these models suffer from a similar quandary is unsurprising, and should almost be expected.