on mine, I tried to get that flag out and when I finally pulled it out, little spring was attached to it and now I cant get it back in. I was going to modify it and then reinstall it but that little spring is a nightmare.
Also even if you are going to pull out all of the guts and install the plug, you still have to figure out how to get the lock out. I was told it takes a special tool??
Or is it a press fit and you just use a punch to drive in out?

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Former LEO & firearms trainer