"Are they sure these are the only docs that Berger grabbed? Could there be anything else missing they either don't know or aren't talking about?"
Maybe not, but maybe copies of all docs were made...or maybe not all of them, like the "notes" - what's that, a yellow pad?
The notes are a ruse if you ask me. He wanted to hide something from the commission. What would he need notes for.
The ploy was to just get the docs out of the secure room the commission was using to search through the record. Can't find what isn't there, and you have no way of knowing what you didn't find is missing.