In 2008,
Heritage Auctions sold this box, from a different maker:
It was described as:
"
Discarded Wooden "Army Bread" / Hardtack Crate Found Near the Gettysburg Battlefield Shortly after the Battle. Measures 18" x 25 ¼" x 9 ¾" high pine wood crate assembled with square cut nails and stenciled on the bottom, weathered / faded," Army Bread/From/Kendall Bros. & Co./Cor. Powers (large stain)/US/Sub/Dep/June 1863." Doubtless issued during the battle. Excellent sound condition and a most unusual Gettysburg artifact."
Don't know the winning bid -- have to register to find out.