Same as Audits
It's the same story as IT audits. Make sure there's something obvious for the auditors to find, and report on. Preferably something you've already told your boss about months ago. If the auditors don't find something to report, they're liable to inflate something irrelevant into an issue that they can report on. The last thing they want is to have nothing to report on, and nothing to justify their fees.
However, I'd hate anyone to think that this tale is just another example of Y2K panic where nothing happened. Nothing happened because a lot of time and effort went into ensuring it didn't.