Thanks to Susan Stickles for supplying this copy, from the papers of William C Reiff!
91st PA plaque on Pennsylvania Memorial, original form
(see Gettysburg Memorial for the current, corrected, state of the plaque, and a transcription with links to the men's pages)
on back (by William C Reiff):
"This card is supposed to contain the names of all officers and enlisted men of the 91st regiment of Pennsylvania. who were present and took part in the Battle of Gettysburg July1-2-3, 1863. Theses names in this form were photographed from a bronze tablet which is now in place in the Pennsylvania Memorial Building at Gettysburg, which was dedicated September, 1911. The certainty of the correctness of this entry of names here is based upon the fact that the Regiment was mustered for pay on the afternoon of the 30th of June, 1863 at or near Union Mills or (Liberty?), Maryland the day before the opening of the battle. Those only who answered as present there were deemed as being in that battle."