Upload & Sell: Off
First off, let me say that I don't own a D600. I would love to, but it's not in the cards... or at least, not the credit cards. Second, I could care less about this detail. But honestly, the amount that I care is very, very small.
A tangent: In the pro audio recording world, one of the most popular sets of monitors (speakers) was the Sony NS-10. And they sounded like crap. But they were very common thing to find sitting on top of mixing desks, in listening rooms, etc. And oddly enough, despite sounding bad, some absolutely amazing records were recorded, mixed and/or mastered while listening through them. Why? Because the engineers knew how to use their tools. They knew what effect the speaker has on the actual recording, and how it would sound differently elsewhere. So they understood their tool.
The LCD is just a tool. If it's miscalibrated, or has a tint, then you can get used to it. You can learn it's quirks and tendencies, and say to yourself, "Self, the picture looks a little green, but you know that it's actually not that green". You can take that picture home, and work further on it in your well-calibrated monitors.
Or you could just just say "fuck this crap" and return the camera. That's OK too.
Personally, I think I could get used to a little green, in light of the step up from my current gear that this camera would provide. My D40's exposure isn't perfect; it tends to overexpose. No biggie; I know how to handle that in Lightroom. No tool is perfect, and I'm a little quirky myself.