Actually one would expect Manafort’s house to be brimming with notes as he was preparing testimony for the Senate Intel Committee that very morning. This was a case of the Special Counsel interfering with a congressional investigation.
When I owned a business that made classified items for the US military none of it ever came home with me in any form. I sold that business but keep the division of information intact.
With the vengeance that Mueller clearly has for Manafort were I him I would of been doing my prep work for Congressional testimony in my attorney's office.