No, they go on top of the ribs, between the LE and TE sheeting. Since there can be differences, they can't really be laser cut, as the length won't always be exactly the same. It's a simple matter to put it against the LE sheeting, and us a razor saw to cut it off even with the TE sheeting. I usually cut it a touch long, then trim it with my sanding bar to get it exactly the right length.