Quoted: If you look at the knob, there is a pin that you must push out first before removing the screw. Good luck.

Putting that pin back is is NOT one of my most favorite things to do.  FYI when you knock that pin out, there is a ball detent and spring installed in the knob.  Be sure to catch those when they fall out.  They need to be reinstalled when you go to put the knob back on and drive the roll pin back in.  Here's where the fun starts.  Ever try to tap something in when balancing two very small other things in one spot while holding a larger thing in your other hand.  Oh and don't forget that the hole in the windage knob has to line up with the hole in the index screw, while the ball detent wants to line up with one of the detent positions on the sight base which naturally won't help you line up the two holes mentioned first.