I should add that there are a lot of models that carry the "green label" designation. Some are rarer than others, and worth more than others. I have seen green label models for as little as $1200 and models like my GC, which I sold for $2550.
There are a lot of factors which determine the value, I discovered. My GC was a very early model, serial numbered in the very low 200s, with an A1 receiver. Because of that, it did command a somewhat higher sale price than a later model, which I have seen for sale at about $2200.
If I held out, I probably could have gotten even more for it. I spoke with a fellow that sold his same model, serial numbered in the low 300s, for $2800.
The best thing to do is to research the particular model you're looking at. Don't let just the fact that it's a green label make you spend more for the gun than it's worth.