I'm sure I'll be corrected, but I believe the black sight was a 'mid-year' change because S&W received complaints about the visibility of the rear sight. I do not believe the 'white outline' had been invented yet.
Most of the ones I see are black. From my understanding the original stainless sights reflected sunlight back in the shooter's eye. Most people had them replaced with the black sights.Most of the 66 no dash revolvers I've seen have stainless steel rear sights and blades with no white outline.
we have a no dash, in the #9K 6000 range here ,has a "stainless" rear that was indeed 'blackened' over an all stainless sight body.....its the early ALL stainless, in the boxes that get the big bucks and are sought after, BUT LE requested soon on, to "darken" the sights and so something to make them 'pick up' (see) better...........
so how far ( high) the "no dash" goes is beyond me .![]()
The early no dash model 66 revolvers came with the silver colored stainless rear sight assembly, and a plain ramped front site, unless a red ramp insert was ordered. Later no dash model 66 revolvers, such as the 7K XXXX model I own came with a blackened stainless steel rear sight assembly, and a standard red insert in the front sight. The blackened stainless rear sight assembly is stamped, on the underside, with an S.
I don't know exactly when white outline rear sights began to show up, but most early model 29's, circa late 50's, I've seen are equipped with both white outline rear sights, and red inserts in their ramped front sights.