Early on, there were so few people mining that practically everyone had a "large volume". As such, if you pick any arbitrary bitcoin transaction at that time, it's highly likely it will have originated from a large volume source in the recent past.
I think it's more likely a case of mistaken identity; there are many people in this world, and I think that the chance of someone remembering someone from 3 years ago that they saw for half an hour, tops, with sufficient accuracy for a positive ID is much lower than the chance that there are simply two middle aged asian men who look vaguely similar. It's also improbable that "satoshi" would fly across the country for this purchase. One person's word is certainly not compelling to me.
Even if that account is 100% accurate, it does not link the man who paid with bitcoins to satoshi, but merely to Dorian. The HN link relies on the flawed NewsWeek article to make the further connection from Dorian to Satoshi.