To get to the motor is easy enough, to replace it is a bit of a tedious job. Check out the article on Pelican parts or in 101 projects on this. Take your time, as there are lots of little plastic bits than can break on the strip down.
I can not think of manual wind....so please let us know if you find one. Remember to mark all the wires on the elect windows switches as they are pain.
Were elec windows an option? If so I would guess the manual mechanism is just enhanced, so it is likely that there is a manual wind.
H