If you traffic the late model pinball restoration threads you will find the metal mender products out there are utilized often to rebuild a worn kick out hole. They then touch up and clear or cover with a surface protector made by Cliffy or others.

I've used metal epoxy to build up the edges of playfield holes on a Dr. Who and a Creature From The Black Lagoon. The fixit creativity is alive and well in all sides of the pinball hobby.