This is very wrong.
He may just not be clear with this... but he's really talking about PowerMac 970s. (As OS 9/X couldn't run on a PowerPC 970 in isolation).
ALL new hardware from Apple has required tweaked OS's to allow them to run... in the old days, called "enablers"... because there are slight changes to the hardware.
With these machines, not only is the Processor new, but the subsystems are new. You will not be able to run OS 10.2.0 on the new PowerMacs.