My buddy just picked up a Colt "Night Government" the other day. It is a full size government model, black in color with factory night sites. The serial number is NTG2XX (last two digits omitted). We do not have a clue as to it's history. Can anyone shed some light on this for us. It is a great looking gun and has seen little use. The only downside is that the night sites are well past their prime as far as illumination goes. He was thinking about replacing the sights but doesn't want to destroy the collectability aspect of this gun, if there is any. Any info appreciated. Thanks.