Even looking at the pictures that people are using to demonstrate its greenness, it still looks predominantly yellow/gold to me...just with a greenish tint.
By contrast, the green color of the wraparound tunic is pretty obvious.
Whatever the costumer's intent, if it looked yellow/gold on camera, I'd say that's what the color was in the fictitious setting. George Reeves may have worn a brown and gray costume for black and white television, but Superman was always wearing red and blue.
Well put. I own a "Phase II" command shirt made by Theiss in 1976 to match the third season color so that they could reuse old uniforms with new and they would look consistent. While it is definitely not a true "gold". neither is it remotely "lime". The problem in defining the color is that it is simply odd. It is not a "pure" color in any way shape or form and any difference in lighting – indoor, outdoor, florescent, incandescent, bright, subdued, etc – shifts its color. But the thing to take away is that it is NEVER truly green, only "green-ish". Chartreuse is the closest descriptor though I would qualify it and call it "gold chartreuse".
Here's what mine looks like under the bright lights I used for the photos, not unlike studio lighting:
There can't be any doubt that the producers knew the shirt filmed primarily as a gold color – they weren't blind. And since every portrayal of the color since the show first aired is "gold" of some type (think Mego action figures) I think that puts it to bed.
Note that there are some colors that simply cannot be accurately photographed due to the fact that film can't record the same spectrum that our eyes can see. Florescent colors, for instance, can't be captured correctly on film. They always look drastically different than the way we see them. The command color is an example of this effect, though not as extreme.
As for Kirk's truly green wraparound, I chalk that up to "he's the captain". Theiss made no effort to make it the same color as the regular command shirts so his intent is clear to me – make the captain stand out.