Quoted from ThePinScientist:If anyone reads this thread because their own numbers get rubbed off or fall off, I have decals available. Free shipping. ThePinballScientist.com
Hopefully it helps someone else out.
I used decals like these a few years ago while restoring a Bally Old Chicago (the owner included them with his machine.) They turned out great, but as I recall, they were a lot trickier to install than I expected, until I got the hang of it. Be sure your order provides a few extras. You'll need them.