If it's not drilled and tapped, it'll need to be drilled and tapped. Completely take the bolt out, after drilling and tapping make sure the screws used do not enter into the action but remain flush with the frame. If the screws protrude they will interfere with the bolt moving back and forth. I prefer the drill and tap to the versions that are held on by the action pins.
Aimtech has a non drill mount that will fit : Part number ASM8
Either or, use loctite with it.
