Can't they be green to some and gold to others?
Not everyone perceives colours the same way. Case in point, the dress.
"The sky is blue."
"No. it's purple."
Someone is gonna be wrong.
If a color blind person looks at a color and sees it differently than a non-color blind person, it doesn't change the color.
In the case of the uniforms, on set, they lean towards avocado. On TV, they were in the gold area. But the longer-term evidence and later dialog support gold.
And, as it's been said, if they truly wanted Kirk's command tunic to be green, they would have made sure it turned out green on screen. This wasn't the first color TV show ever. They just weren't all that concerned about it. His standard duty uniform was gold. The dress uniform and his wraps were green. But also different shades. Those didn't match either.
Lots of stuff didn't match. Lt. Masters of Engineering wore a science blue ensign's uniform.


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