Stylometry was known at the time, Hal might have changed his. People have been using computer stylometry for years to rule in or out pretenders to be Shakespeare.
He would've had to mimic someone else in that early crypto-sphere who does match the stylometry much much better.
That person was also familiar with Hal's PoW implementation (where Hal mentions it was an implementation of this guy's concept) 3 years before the Bitcoin paper, but attempted to obfuscate that fact.
Stylometry was known at the time, Hal might have changed his. People have been using computer stylometry for years to rule in or out pretenders to be Shakespeare.
Emails can be sent with a timer.