How about luminova paint. That is what Breitling and others use to make the dials and hands on a watch glow in the dark. It may also be regulated by the NRC, I don't know, but it is very popularly used by a lot of watch companies. Even Rolex has gone to it. The first problem would be to find a "watch maker" who works with it who wants to fool around with a handgun slide. The second problem would be how well it's going to stay on when it is constantly exposed to solvents oil and the elements. In order to explore those possibilties you would need to start searching the net for someone who specializes in reluming watch dials and hands. There are places that do that. I don't have a link but there was a watch person in Flagstaff, Arizona, who did do faces and hands a couple of years ago because he did a watch for me.
Whether or not one needs night sights on a pistol like a Rohrbaugh is another subject altogether. I personally think that one might be very disappointed with the result and with the utility. The Rohrbaugh is a fine pistol for it's intended purpose. It is not nor was it ever intended to be a 50 yard match grade gun. It is a fairly close range defensive pistol whose chief asset is it's small size and quality. It is a lot better than a "Push/Pull" gun. That's a term I coined in my classes for a pistol for people who can't shoot or seem to learn to shoot properly. It means Push the gun into the target till the front sight disappears and pull the trigger till the target either disappears or you can see through it. It's a facetious way of dealing with people who can't seem to get the light to come on about trigger control and focusing on the front sight and was always delivered with humor and good nature because as most of us know, in real life, it won't work for a variety of reasons.
But for those who want night sights, if you think you want them, it's only money....get what you want or think you need. Even if it's purely psychological, if you think it helps it probably will. As for me I'll do without them on these mini guns.