That's a great question. In his book, it only states, "List of Surviving Sharps Berdan Rifles - Correct Profile. Sharps New Model 1859 military rifles, reported as having double set triggers, fitted for the angular bayonet, and inspected by John Taylor, [(JT) cartouche on reverse of stock upper wrist]." I've checked a few other books that I have by Marcot, Sellers.... but I see nothing listed in those....that I can find. I, too, would like to know exactly when & how this list was generated and if there is a more recent list after 1988? If anyone has any leads, please let me know.