No, it doesn't. I called 1-800-MY-IPHONE and purchased it right over the phone. Got a confirmation email the next day.
From an Apple email -
"After that date, if you would still like to purchase AppleCare+ within the first thirty days of receiving your iPhone, you can call AppleCare at 800-MY-IPHONE or visit an Apple Retail Store."
I'll have to try this when my phone comes on Monday.