Door Striker post?

Quarter panels are not off yet. Just able to peek in through the rear window area with rear interior panel removed. That clasp on the back, does it look stock to anyone or was this an older style repair method? Who knows how many times a 52 year old car has been Mickey mouse'd around with. So best method seems to be the plate from one of the various suppliers welded on back side then just screw original striker post back in? Seems strong enough for me. I can't feel any play whatsoever in my door hinges but rubber seal has deteriorated quite a lot. Maybe it has been striking to hard when door is being shut?