I know every kanji means something ("meaning something" is something kanji are made for, you know) and Satoshi (the Satoshi, I mean) never wrote his name in kanji by the way. But 中本聡 is something more "bitcoin-ish" than some 山本ヒロト, don't you think? So that name isn't really something unlikely to make up. I'd say randomly making it up is really really more likely than being the Satoshi's real name.