On a pistol with a factory optic cut, the red dot goes on an optic plate with the same footprint. On a pistol without optic cut, it goes on a red dot mount in place of the rear sight. See Optics ready plates and Red dot mounts.
Yes, if there is a plate or mount for your pistol with the same footprint as the red dot. Each red dot names its footprint in the table above and in its description.
Can I install the red dot myself?
Yes. Screw it onto the plate or mount with the screws that come with it. Put a drop of threadlocker on each screw and tighten it to the torque given by the maker.
