Quick update: Bought a rebuilt button panel from GET-T and installed it today. Fairly easy process and the game looks great now! Buttons are super bright and very sensitive to being pressed during play. The only issue I had during installation was that the rebuilt panel top face plate was slightly different from my original and I had to switch the new face plate with my old one in order for the new button panel to fit into the game properly. Maybe different WMS games use slightly different face plates? In any case, I think GET-T has the rebuilt button panels on sale for $245.
I also bought a complete set of replacement button screens and will use them to rebuild my old OLED panel. They were on sale for 9.99 for the small buttons and 19.95 for the large button. I'll keep that one for future use.