34 pickup striker plate

[drfromnc]

I ordered new striker plates and see they come with 2 screws per but the door jamb mounting points are missing a nut. Each door jamb has a cage nut in the outer most hole but the inner most slotted hole is just that , no nut. Where do I get one or alternative solution?

Also I noticed on the back side of the only original striker plate I could find appears to be a very thin piece of paper or some other material. Anti-squeak?