Brownell's (and probably other sources) will sell you both standard pin and roll pin punches. They would like to sell you starter punches as well to minimize your chance of slipping and marring the finish. I think the front sight pins are 1/16 inch, but somewhere I saw a reference to needing a .05-in (1/20 inch) punch to get them out. I'm hoping someone will address this question for my benefit as well as yours.
I seem to remember there is directionality to these sight-retention pins. If I recall correctly, with the muzzle pointing away from you and the barrel at the top, you drive them in from the right and drive them out from the left. If I got this wrong, somebody PLEASE tell me soon, as I have a set of punches on their way to me from Brownell's.
David Wilson