for comparison,
I just ordered a series 7 watch,
Ordered on Friday the 8th
card charged on Tuesday the 12th
watch left Shanghai Tuesday the 12th.
delivered on "launch day" Friday the 15
so as Wilberforce said, they charge when it actually ships or slightly before
it's been the same for things with a long lead time, it might sit as pending on apple's site for weeks/months, but they don't charge till it ships. There is also no hold on the card during that time, They just put it through at shipping, not sure what happens if the card declines at that time.
BUT... saying all that, since launch day for those is Tuesday, it should probably ship & charge today or tomorrow