FWIW, I have never found paint on a front sight to destroy the value of any handgun. It can be removed fairly easily without a trace left, and that leaves your gun as pristine as it now is. Adding the plastic would leave a permanent mark, however. I have used Testors enamel model paint with good success for a number of years. Any of the florescent colors will work well and there are several choices of color. My preference is for the flo. green. I also recommend getting a bottle of white and making your first coat a thin coat of white. This seems to me to make the other color choice more vivid as well as helping it to last longer during normal use. I also have found that using a good sturdy wooden toothpick to carefully apply the paint works better for me than does a brush. I do not like for the paint to be too thick, and I can control that more easily with a toothpick as opposed to a brush.
This is my opinion, of course, provided here for whatever it might be worth. But I wouldn't recommend the paint if I felt it would devalue your gun. It certainly will be a better option than those SS sights F&R. And it is an inexpensive way to solve your problem with the added benefit that you can easily change the color if your first or subsequent choice does not satisfy.
