The PPC lineup went 601 then 603+604. 603 was lower end (performa) and mobile and 604 was powermac until the product lines got so splintered that everything was in everything.I see the Mac Pro being the first with the M2.
Two thing said at the event, 1) that will be the final M1 release, and 2) there is only one product remaining to move to AS.
That seems to indicate they will come out of the gate with the highest performance M2 first, the Mac Pro. I predict it has four M2 SoCs. Down the road, other product follow, M2, M2 Pro, etc.