Why would you need Boeing 707-300 series manuals as there are not any [civil] ones left flying, the only ones still flying are in military hands and I would think they would have their own manual copies?
Having worked on Boeing 707s [long ago in the past] the only manuals I ever saw for them were paper versions and the aircraft had gone from service long before Boeing started to issue electronic copies of manuals, in fact I don't even remember seeing the microfilm versions of the Boeing 707 manual, just the paper manuals.