You have a pretty good grasp except that the staked nut does not come out by itself and must be drilled.I dont know if I am thinking of the same thing that you talking about.
The staked nut on the adjustable S&W rear sights I am thinking of is retained by the screw that is center staked.
These are designed not to be reusable.
To replace the blade, you need to replace the nut and screw.
S&W sells the kit with all three pieces.
The best way to remove the old screw an nut is to over tighten till it breaks.
It wont take much to break it, and no damage will be incurred elsewhere.
The nut will come out one side, the screw the other.
No need to drill anything.
But be careful, there are some tiny springs and detents involved.
I have already over tightened the screw and snapped it as designed. The staked nut is still in the sight body. It needs to be drilled out as designed. I'm skeptical but happy for everyone who has actually accomplished a rear sight blade replacement without having to drill out the staked nut. Mine requires drilling.Never had to drill one out.
Here is a link with the procedure.