To answer the other part of your question, I believe "most" L-frames came with the W/O sight from day one. Most of the black rear blades I have seen have been on short barreled guns, too, or special distributor runs. Another source is Numrich Arms, & you'll need to buy the screw & nut to go along with the blade. I believe it's available as a kit too. If you've never changed one, it's a good idea to place the gun in a plstic bag so the detent spring & plug don't fly across the room when you screw the windage screw out. Good luck with it, sir! Oh, just to add, I find the only thing black sights good for is aiming at a black bullseye, using a 6 o'clock hold in broad daylight. For anything else, to my eyes they're almost useless, but I'm old, & don't see as well as I used to.
