I thought that fiber optic sights were the "answer" to my Ruger MkII sighting issues. Outside, they worked great, in an indoor range, just as bad as the stock sights. I used to frequent the local indoor range quite often. I have since put a RMR on it (knocked out the rear sight and pushed the mount for it in the dovetail). Now, it's the tits. I imagine the same outfit makes a mount for a 1911 (depending on dovetail cut).
Moral: if there isn't a ton of ambient light, fiber optic sights are limited...