the repair work will take some time. Even if the holes were only an inch in diameter (likely bigger though), mixing the right shades of marble dust to match the striations in the original, it takes time for the stuff to cure, there are at least 3 holes per letter, then sealant, then buffing, then maybe other adjustments as needed. A good mason that is very experienced with this stuff could probably make it so you can't see the damage that was done..... but what are the chances that someone like that will be hired? There's also no good reason the work can't be done in the open. Workers on scaffolding is common. They didn't have an issue with that when they were putting those letters up. It always takes far longer to fix something than damage it.
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