That user was not referring to where the bus currently operates. They're arguing that 4630 was the highest numbered 2009 model of the NG hybrids.
As for the debate at hand, I remember TTMG and other older rosters categorizing the 4600s at JFK as 2010 models in their old roster pages for years. Most sites, including mine, followed that piece of info for years. Now TransitMan is stating that only 4656-onwards are the only 2010 models. It would be nice to see a definitive clarfication, though that in itself is a rather small and somewhat insignificant thing to argue about.