"Familiar Faces" at the Smithsonian

An art piece with mirror and familiar faces such as Abraham Lincoln and Andrew Jackson invited a photo opportunity for us when we visited the Smithsonian American Art Museum in 2007. Our faces, familiar as they are to Julia and I, won't be familiar to you, but you can no doubt recognize many of the others:
Clara Barton, Andrew Jackson, Martin Luther King, Mary Todd Lincoln, ??, Abraham Lincoln and Walt Whitman

Although I have no info about this piece, the model beside us gave me clue to the exhibit at the time, Temple of Invention: History of a National Landmark and piece check list for this exhibit mentions photos of some of these people