Those are TPS rings and base. The base is for a 700 short action. Cut the rear portion off, dremel away the little recoil lug (both steps are easy), cold blue, and it's good to go. Ken Farrell sells an XP base that's ready to go but it's really tall and heavy. TPS rings are impressive. I lap all my rings and the TPS base and ring setup actually didn't need lapping. http://www.tacticalprecision.com/
I don't know about Seekins. Yes, a one piece 700 sa base will work but you have to remove some of the rear of the base. And if the base has a recoil lug, you have to dremel it off.