Like the factory, a lot of dealers were caught with large stocks of 6-digit panels when the changeover to 7-digits occurred. The mod shown is very similar to how the new 7-digit display was prototyped . Molding the board from 6 to 7 is not difficult for an experienced tech. It only requires a few spare parts and a tiny circuit board as shown. I would rather just move the working glass to an original 7-digit board but these days if you want to keep the game running with PG panels you do what you can.