No, there is really is nothing to sync... the two motors are both hooked up the the same x axis out (on the) controller. So, both are sent the same pulses at the same time. Since both motors are the same specification, and the same size screws, nuts, belt drive or rack and pinion setups are used, it really can't go out of sync unless a motor misses a step. You could also have a motor on each end of a single screw and one motor is wired opposite (backwards). The same principle applys.