That's not what I meant.
If those numbers represent the three names mentioned, how does putting them anywhere on the face, above it or on the posts help anyone ?? It's a dumb thing to request. And dumber to tell someone you'll figure something out.
Now, if they represent three other/or new locations, it's still a dead end.
That is why I said, it's time to explain to the customer this is a bad idea and revamp the entire thing..... or just let it go. No matter what you do, unless it's the law to have numbers on a sign...... it's just gonna be confusing... for anyone.
If there's a mistake made, then make the patch look like it belongs somehow. Going bonkers with the numbers, not matching the style of the sign itself, by not being backlit or identify anything just plain s^cks..... and it'll look it