Yes, it had several private pilots on board, some of whom were attempting to take over the aircraft.
One mis making the assumption that the hijackers would be disabled, and then the private pilot would find this manual, and land the airplane (a walter mitty fantasy for all private pilots, I believe).
Had FL93 not crashed, it would have been shot down. Interceptors were enroute, but got there too late.
Most flights have pilots jumpseating on board, or deadheading, or simply traveling, It's very common to have a number of pilots on board.
Making operating instructions available to traveling private pilots probably won't make a lot of difference, I suspect. If the issue is flying the airplane after the crew has been killed or disabled, and the attackers neutralized, then perhaps a higher priority ought to be getting to that point. Before we worry about finding a way to land the airplane, we ought to concentrate on keeping it under friendly control, or in the event we're beyond that, in taking control back.