HI Rocky. I too have one of the old Redfields with the aperture screwed on the back of the one piece base. A great idea that, thankfullly, I've never had to use. I guess an enterprising guy could mfgr them for existing Leupold, Redifield, Millett etc., bases since their scrwed on and would only require drilling & tapping of the rear base.
Question: If I use the AO rear sight in the Weaver base of my M-94 Trapper AE, will I need to add a higher front sight?