Looking through the net for archives, yes, it does seem the 21.5" iMac shipped with a 9400m in October 2009. The 300M series is from January 2010 and the actual 320M first appeared in Apple computers in April of 2010.
Doesn't make the Intel numbers any more impressive after 13 years in the game, but nonetheless, it's not as bad as "2 years behind", they're just 1 year behind now.
I love how all of this FUD is coming from someone who purchased a machine with a 2 going on 3 year old processor in it.