It is a TC primitive sight for people that want/need a fixed sight for their gun. No longer made or marketed. The screw holes were elongated to use factory sight holes on their various octagon barreled models.
It is usually used with the patridge type blade sight as found on the Renegade.
Lay about a 9/16ths socket across the dovetail and give it a couple light taps with a small hammer. It won’t take as much as you think so, tap and try, tap and try. Also, there will be no visible evidence of the repair when you’re done.