Shoulder belt issue on 68 Barracuda

I made the parts to ad shoulder belts to 67 model notchback. 7/16 fine thread welded onto square piece of 11 gauge steel plate. Secured in place with pop rivets. This was a few years ago.
I still have extra nut plates ( made extras ) but I don't still have pics of my install. I really don't recall which way or what opening I went through to get these in place. The entire headliner was out at the time.