The date on the poster
Sept 19, 1881: James Garfield dies. He was shot on July 2, so the date most people keep is the shooting. This one is the 79 days after.
The bullet didn't kill him. It missed his spine and his major organs. The recorded cause of death is “massive infection including sepsis and pneumonia, after being shot.” Doctors probed the wound hunting for the bullet, and the record says they likely made the infection worse. Alexander Graham Bell tried a primitive metal detector to find the round and failed, because the attending surgeon, Doctor Bliss, kept control of the search and insisted the bullet rested somewhere it did not.
The clean story is that an assassin's bullet killed the president. The receipt says the wound was survivable, and the hunt for the bullet did the damage. Even that splits: one biographer says the infection was inevitable, another that in today's world Garfield would have gone home in two or three days. The record keeps both.
July 2 is the date on the poster. Sept 19 is the one that did the work.
Source: Wikipedia, “James A. Garfield” (cause of death; Bell's detector; Bliss; the two biographers), read at the source, Sept 19 2026.