The Meprolight FT Bullseye Handgun Self-Illuminated Night Sight comes with the necessary screws to mount to the existing rear sight dovetail. You will need to select the correct model for your specific handgun so the Meprolight FT Bullseye Handgun Self-Illuminated Night Sight dovetail adapter will properly fit.
The mounting hardware in the instance of the Rear FT Bullseye is a dovetail piece (those come attached with the body of the FT Rear in every purchase) that fits into the rear dovetail cut of the slide, along with the screws that connect the body of the FT Bullseye to to dovetail mount.