1972 Dodge Demon seat medallion backing plates.

I brought new ones we have bucket seats,but we tried to use different backing plates 1/2” push on washers now they are coming loose. We couldn’t find correct OEM backing plates. We finished rear seats the same way recovered them and had them in the basement and mice got in them and we had to redo them. It has been quite a uphill battle.I know if you have to cut up the seat to get the medallions and the backing plates out you may want more for them.