I don't think the color was popular at the time, I assume that as I see very few in Winchester Gray and I've been looking for ages. Green certainly was popular, lol.
It was more popular than black! (TX9). But yeah, most make/model break downs by percentage show GA4 was usually only 2 to 2.5% of total production. My '71 Satellite Sebring Plus is a GA4 car.