While reupholstering the seats, I found that the button for the seat back lock had come off of the hinge cover. I've seen this before so I know it's not uncommon. Came upon a super easy fix for it. I got a C-clip that was just snug on the raised cylindrical part of the hinge cover, put the button plate in place, notched each side of the cylinder with a hacksaw blade, and put the c-clip on. Holds the button nicely for all of 40 cents and ten minutes.