No. The motor will need to spin in the opposite direction, but the prop will still spin the same direction. You could let the motor spin the same and replace the prop with a 'pusher' prop, but this isn't necessary. Simply reverse two wires on the motor and remove the prop and reinstall it so that it still faces forward. In the front, the markings on the prop face away from the motor, with a pusher, they will face toward the motor.

The prop in this picture is a standard prop mounted facing forward, on a motor spinning clockwise. The nice thing about pushing motors. If this was a nitro engine, I would need a pusher prop because the rotation can't be changed.