That's a beauty!
.146 blade height. Part numbers, black assem 05787, 05109
white outline 04091, 05900
Copied from the faq:
Removing Rear Blade
To swap the rear blade:
When changing the rear blade on S&W revolvers, turn the windage screw clockwise until the screw breaks. Then remove the nut by unscrewing if from the base. Use a plastic bag to catch the tiny spring and plunger that is located inside the screw head.
Reinstall the parts and tighten the retaining nut fully then back it off ¼ turn. Use the stacking tool and crimp the nut. Job done!
Tools look like this:
Rebuild kit looks like this:
