1/23/09 - It appears the update has finally showed up on iTunes.
Version 1.9.6 of the U.S. Historical Documents application has been approved by Apple and should be available for updating soon.
Here are the release notes:
Added President Barack H. Obama's Inauguration Address
Added The Federalist Papers (all 85)
Added The Virginia Resolution
Added The Kentucky Resolution
Added The USA Patriot Act
Updated the Gettysburg Address to use the officially accepted version which Lincoln signed (Bliss Copy)
Fixed some minor misc. formatting errors in some of the documents.