I don't think the factory would drill through their name. I was wrong about the sights, they did make them for 121's, but I don't know what the spacing was. If you go with a tang sight, get the Lyman. I have a Marbles on mine, but only because it had one before and now there's a hole in the wrist to fill, Marbles used a screw at the back of the sight. The Lyman is more nicely made and much easier to adjust.
