For shooting fine/small groups with a handgun like the 686 (any revolver really) a gold bead is NOT the answer. The very best/smallest groups you can fire with a handgun will be fired by a post or solid black ramp front sight with a "U" rear sight. Fiber optics, red inserts, beads, etc will not shoot as well as a simple post or black ramp front sight. Using a six o'clock hold will work best.
Yep. But it depends on what you're shooting at. If you're punching paper targets, the flat black sights as presented by a Boughman (a ramped front sight that appears as a post when sighted) or Patridge (a straight post) sight are the recognized iron sights to use and have been for more than 75 years. But if you're using a center hold on any material that doesn't allow you to see the front sight centerd, vertically and horizontally, you're going to lose some precision.
The problem with a gold bead front sight is that it does not allow you to get good solid elevation precision due to the rounded top. Too, the round gold bead reflects light from the side and will play havoc with your windage, generally moving groups away from the light source. A flat faced gold bead does better in that regard but still has the elevation problem. (Hard to tell when it's exactly level with the top of the rear sight.)
If you're interested in hunting, in varied light conditions, and where the finest, pin point accuracy is not needed, or for SD use in dim light conditions, then a front sight that's more visible is needed (colored paint on the post, a tritium or white dot, etc. It allows you to pick up the sight, faster and to center it better in the rear sight notch, than one that's blending with the backround due to it's coloration.
For my field use guns, I paint white out typewriter correction fluid on my front sights to help me pick them up in dim lighting conditions. Works well with my lever guns for deer hunting here in KY's timbered ridges as well as my short guns. The difference in precision with the handguns is less than 1/2" at 25 yds in group size, a trade off I gladly make.
HTH's Rod