Ok, it wasn't pitch black, the gun was probably in the room for about 10 minutes or so, we snapped alot of pictures during this time changing the settings on the camera. That picture was taken in a "near" dark room and (I'm no photographer here) but my brother had the shutter set and it would take 30 seconds to take the picture. Excuse my "technical" terms when it comes to photography.
EDIT - I just asked my brother some technical terms and he is what he said "Canon 300mm f/2.8 IS L lens, at 30 seconds f/10, ISO 400"
So, I hope this helps, the sights aren't quite that bright, but he is a good photographer so he made them stick out more than they do, the gun was actually about 15 feet away from us in this room.