Mine had babies three times without any hibernation... so be prepared, it can happen!
Concerning the color.. this one of the most interesting (and hard to understand) question. Regardless of the original color, they all can become almost black. MIne are bright green, one is lime green and two brown ("golden"): all of them sometimes become black, seem scared of everything.. and after few days, everything is ok again. I checked temperature, light, humidity, shedding time.. Nothing seemed to matter. I had to move them to a small box for few weeks and I expected them to turn black and scared and they kept their brightest colors. Once again, after a period of bad mood and black color.. I found eggs! So I thought it was like a small "hibernation".. but next year they laid eggs during their bright and happy moment. One of them (the lime green one, a male) is particularly subject to mood changes (I like him, is somewhat psychotic but is also smart and funny). What can I say? there something of personality, and probably something in the environment I don't see.. That's why I like them!