Your "intuition" about all of the books having been published (i.e. your comment "I'm sure"), does not translate into facts. Where are your facts backing up your certainty that the 100 books have all been published? I do not think the author of the article would risk his reputation stating they are previously unpublished unless the author was relatively certain about that being a fact.
North Korea insists it 'regrets,' not apologizes, over mine blast that killed 2 South soldiers (AP)
from the article: Rare medieval Hebrew prayer book to go on display in Israel