Mr. Deavers, although not an original paper document, I do see the clear signature of Squire Boone affixed to his Vicksburg parole (signed as Squire Boone, Col 15th Ark Vol) in his individual service records which are available by clicking the red box at the top of the page.

There are a few additional documents, (requisitions, etc) included in his file that are signed similarly in his own hand (albeit copies of said documents).

Good luck and good hunting on your quest.