No, he didn't tweeted about "making sure" of anything.

Elon tweeted "I’ve asked the SpaceXAI team to preserve any rare books in a library and scan them the hard way vs just cutting off the spine and scanning"

which is no sense a credible source for what he actually asked SpaceXAI team to do, or if they are doing it, or what they were doing before yesterday. Elon has an extremely long and thorough track record of lying.

https://xcancel.com/elonmusk/status/2081844165881594362

Sure, I'm ambivalent to his veracity.

The problem remains either way. Small operations around the globe are debinding rare/unique books. I'm involved with an organization considering (not strongly) that exactly. It's bigger than a single man's tweets.