It isn't considered a true green because there is no blue color pigment in the geckos. The color for them is created by a mixture of the yellow and black pigments. And I agree 100% that those cresties do not look like an olive green, but perhaps that just means that they have more black in the mixture than yellow. I am not in any way skepitcal about the color, I'm just trying to let people get a better understanding of how it works since no one seemed to know, and I'm sorry if that's how I came off to you. Trust me, I believe you completely, just trying to educate and be educated.
And, hey! If you are worried about selling the babies if you breed, I'll take them off your hands!