Yes there is forward and reverse. There is fully proportional speed control as well, BUT, the deadband will be very small, and full speed will happen very suddenly unless you get very brave and modify the timing components (I used to have a link to a robotics site where this was explained for Futaba servos, but I've since lost it) OR just use the trim tab alongside the speed stick an an "engine room telegraph".
Obviously, the original servo motor is ideally suited to the servo electronics, but has the disadvantage of a very short shaft. Some CD player motors are a good substitute, similar electrical requirements, but a longer shaft. I got mine when investigating dead CD players before letting the trashman have the rest.