I believe one of the early maps of the americas by Amerigo Vespucci was found in a similar way. Re-using paper to hand making the binding, padding the covers, wrapping the bound signatures before the outer leather or board was added was surprisingly common. John Le Carré uses it in "the perfect spy" as a mechanism to pass secret information to an amateur book binder.
It speaks to me of Robert Grave's fictitious account of Claudius deciding rather than hiding them, to leave his (fictional) autobiographical scrolls just lying around, let history decide what to keep and what to dispose of.