The main problem replacing them on a small scale is getting the vials cheaper than Trijicon can get them for. If the sights are that old then I say they are probably Trijicons. Chances are if you REALLT want the glow in the dark sights then you can probably find the same model that is on the gun and replace it for about the same price as repairing the sight. My humble opinion is that sights were ment to be black and if it is dark enough to see the tritium glowing then how can you properly ID a target? In SWAT situations I think they have a purpose but for me probably not. I think the average guy is better off with a good Surefire light. Then again I carry a MKVII(no sights) ;-)
L8r
Conley Janssen