I really don't see the need to replace. I have fired a pistol at night in combat. Here are a few facts from that experience:
The muzzle flash in low light or darkness impedes the ability to aquire a sight picture for a follow up shot or shots, regardless of "night sights".
The key to shooting at night is illumination of the target. The classic LE flashlight overhold is highly recommended.
Night or low light engagements with the pistol are close quarter engagements due to the limitations of the human eye to aquire the target. (i.e., with out thermal or light intensifying optics). A carry pistol with no sights (Colt Defender) is just as effective @ 7 to 21 feet as a tritium sight equipped Commander.
I'm sure there are differing opinions on this. My advice.....don't change anything on your duty weapon. If it ain't broke, don't fix it. Proper technique in night fighting @ close quarter will assure your point of hold is at center mass of the threat, let ballistics do the rest.
Try an experiment ....go out to the range at dusk, set up some IPSC targets and wait till it gets dark. Coax a buddy that has "night sights" on his pistol to go with you. Engage and see what I mean. That .45 ACP is a flamethrower after dark. You will see for yourself if the sight change is worth it.