Hmm. The D7 kit I had back in 1971 was in white plastic.
It's possible that was an unusual pigment run. The one I had back around that period was gray, as was another I saw a kid playing with on the playground in third grade. The unbuilt one I currently have in the basement is also molded in gray. And this one being sold on E-Bay
shows gray parts still on the sprue and in their bag.
The first Klingon AMT kit I got in the mid 70s was molded in BLACK with some chrome parts for the torpedo tube, the little pipes for the sides of the neck, etc.
Cary L. Brown wrote:
Those colors are not "green" and "purple" though.
They're "grey with a hint of green" or "grey with a hint of purple."
To be clear, the article cited says the original model built for the show, "was actually a striking purple-blue and light green."
And then, "[Round 2's] approach was to paint the ship a more overall grey while maintaining a hint of original purple and green. That way, everyone should be able to relate to it. I also weathered it to make the model more appealing, even though the originals were not weathered."