This question is for ALO themselves. My answer is no, there is no way to confirm legitimacy. Except for listening to the cable to see if it improves bass impact, treble sparkle and expands the soundstage.
ALO would be able to verify whether they have supplied the vendor in question with "real" cables or not. It would also be likely that if they are bieng sold below 'cost';, that they are fake-unl;ess the vendor is trying to make it up with high volume sales.