I have a real hard time believing that this day in age, with that level of engineering and chemical research, that simply exposing it to the sun while hunting and at the range will do any noticeable damage. I feel like this stuff in particular has evolved leaps and bounds in the last few years alone. I'd put money on the line that a brand new proof could be left out in the desert for 10yrs and the color may not even fade.
Technological advancement in that process is simply amazing.