The popbumper light sockets actually have a flat metal arm that passes thru the playfield underneath the popbumper components and the wires from the loom are soldered onto those leads. Check uner the popbumpers on the underneath of the playfield and look for 2 flat metal leads on each popbumper that are stapled to the underside of the playfield and each should have normal plastic covered wires from the loom soldered to them. If one is missing wires, that could be where your mystery wires belong.
Hope that is clearer than mud

ME