Depends on whether there was UII in the underlying dataset. It's probable that Twitter kept the mDAU numbers and probably shared them, and Elon's people asked for underlying data that aggregates up to that metric, so they can scrutinize the methodology.

However, saving user identifiable information > 90d is a challenge these days - you have to anonymize it, which defeats Musk's purported goal. (And it might be illegal to share that data w/ a 3rd party.)

I find it very hard to believe that they don't have this information graphed on a dashboard somewhere.