I asked this very question a week or two ago... here was the answer I got:
Now, the issue you're going to have is that we were told in our armorers class that they dont recommend doing this because the pin is EXTREMELY difficult to get out. They put the extractor and pins in the slide and then melonite (the final finish on the gun) the slide. Apparently melonite is a very tough finish and when doing this with the pin in the gun, the pin is locked in pretty good. He advised you will probably break 2-3 punches before getting movement or getting it out.
We didnt even take out the extractor in our armorers course.