I just got a used Trijicon TA31 (looks new) in a trade with some other stuff. It is not a clone/Airsoft replica based on my examination and all of the references I can find on the net. The fiber optic works well in daylight/low light. However, the reticle does not glow at all in a no light setting. I have zero experience with the ACOG (all of my time has been behind a traditional scope or an Aimpoint), so I don't know what to expect. What say the wise ones here. Do I have a problem or is the ACOG functioning correctly?