Jeff,
I just tore out that little leather strip they had for a strike plate / rest and then cut a piece of seal skin the length that would just extend from the edge of the arrow shelf and up the riser the appropriate height. In an eye pleasing shape of course.
Or you can do 2 separate pieces one for the shelf and then butt the facing one down against it.
No need to extend over the edge of the shelf, they only did it that way from the factory to anchor that little strip of leather.