I was searching for some unrelated information and ran across an interesting catalog viewable on-line:
"Catalogue of the exhibit of the War Department at the Centennial Exposition of the Ohio Valley and Central States" - at Cincinnati, Ohio, July 4 to October 27, 1888.
Displayed items were listed, but, not photographed close-up.
Some interesting sketches attributing the common "Broken Shell Extractor" to Buffington and calling the trap-door inspecting mirror a "Russell Inspecting Glass".
(I imagine it is named for Captain A.H. Russell of the Ordnance Department, who helped set-up the Cincinnati Exhibition)?