I would think that they're counting the initial activation requests, not when they actually got done.
The initial guesses at 500,000 sold over the weekend just never made sense. Figure 160 Apple stores. Even if each had 80 units a day (and many didn't), that's still only ~13,000 sales each day for them. Ditto for the 1600 AT&T stores, who probably only had 40 units each, for 64,000 sold a day.
So that would be 26,000 + 128,000 = 154,000 if all had max number of units. Much more in line with what was available for sale and activation.
I suspect that it'll also be revealed that 10-15% were returned within the grace period. Volume issues, poor cell coverage, and buyer remorse (kids who spent their allowance) will be the main reasons.
Still, not a bad sales amount by any count.
In any case, it just proves that most Wall Street analysts are not to be believed. They're in it to make money, and loved having Apple stock soar at first.