My buying experience suggests that most early 6" (and other lengths as well) 686s had red ramp front sights but I prefer the pinned Patridge sight for target shooting, which is how I use my handguns 99% of the time. For hunting, I like the red ramp or a white or gold-dot Patridge - I have a 6.5" 629 Classic with the red ramp and a 5" 629 Classic DX with a white dot Patridge installed for when I take a handgun deer hunting.

I think the pinned Patridge gives owners the option of numerous front sights that the integral red ramp does not.

Unfortunately, my preference in adjustable rear sights is the now-discontinued Millett 100. The S&W adjustable is nice but for me, the Millett just affords a little better sight picture.

Ed