Awesome video. The question is, does the 1980s revolver have this feature. After watching the video I can see that if it does, the hammer should move back slightly upon releasing the trigger (and my 686 Plus does exactly that). If it does, then the 31-1 does have the safety feature. Thanks!
Every Smith and Wesson revolver manufactured since 1944 has all three of those features. Previous to that, there was a different style of hammer block in S&W revolvers.
This photo shows a typical hammer block in a S&W revolver. This is the style that has been inside every S&W revolver since 1944. There were other styles before that, but I am not going to get into that right now. The arrow is pointing to the hammer block. It is positioned exactly as it would be with the hammer down, between the hammer face and the frame. Also visible in this photo are the two other features in Larry Potterfield's video. Just below the hammer at the rear is the part that prevents the hammer from being cocked if the cylinder is open. It is easy to defeat this feature, but I am not going to get into that right now. At the bottom of the hammer can be seen the bump on the rebound slide that retracts the hammer slightly, so the firing pin will not contact a primer under the hammer. Those are the three safety features mentioned in Potterfield's video, and they have been in every S&W revolver for a long, long time. (Unless some idiot has removed the hammer block)
A transfer bar is completely different from a hammer block. Rather than blocking the hammer, as a hammer block does, a transfer bar transfers the blow of the hammer to a frame mounted firing pin. The arrow in this photo is pointing to the transfer bar in a Ruger New Vaquero. Notice the hammer is cocked, and the transfer bar has risen enough so that when the hammer falls, it will strike the transfer bar, transferring the blow to the frame mounted firing pin.
This is the mechanism of a Ruger New Vaquero. The thin vertical piece attached to the trigger is the transfer bar. Normally, when the hammer is down, the transfer bar will be retracted, and the hammer cannot contact the frame mounted firing pin. When the hammer is cocked, the trigger will rock back slightly. This will push the transfer bar up so that it is positioned directly behind the firing pin. When the hammer falls, it will strike the transfer bar, the blow will be transferred to the firing pin, and a cartridge will fire. When the trigger is released, the trigger spring will rock the trigger back forward enough to pull the transfer bar down, so the hammer cannot touch the firing pin. In this condition, no matter how hard the hammer is struck, it cannot contact the firing pin.
Nonetheless, I only have two revolvers and that is not enough. Can one really have too many revolvers?
Only two? You have a lot of catching up to do.