Yep, and I've also been going through some old family books and papers: World Book Encyclopedia from 1935, handwritten college papers form the 1930s, and other books from between the world wars. All were just kept in boxes or on shelves, and are in very good condition, a little yellowed and a little dried, but still can be handled and used without damage to the paper.
Those 1961 BCs would be in excellent condition and could be handled and copied with no harm at all. The Hawaiian AG is spinning some tall tales, to put it nicely.
Depends on quality. Acid-free paper with a decent cotton/linen content can last a very long time. In contrast, I have some cheap pocket books from the late 1940’s which are in absolutely horrible shape...they have turned a deep brown and flake and crumble to the touch. I would think that most governement “permanent record” docs would be of the former quality.