Most sights in my experience, even manufacturer notched ones will need drilled/fitted, though they are much easier to drill out…… Its usually 50/50 at best with notched front sights, trying to force the set pin in on a notched one that isn’t a perfect fit is a bad idea……just drill it out, 5/64” bit with some light oil…..much better than forcing the pin. Always drill so the bit rotates clockwise towards the back of the gun this sets the sight into the dovetail….just a helpful tip
Another tip is set the bit in the retaining pin hole and start it rotating pretty good before pushing it into the sight base slowly, this will prevent the bit from catching and breaking….and they will break, those size bits are small and brittle, buy an extra to have a spare on hand