Through "Miracles" of VOIP, those folks in Boulder can make calls which pop out onto the telecom network in Austin where Apple's telecom switch connectivity is. Apple's phones don't have to be in an Apple building.
But yes because they probably had thousands of phones to make in a limited number of hours ( since end of month deadline looming and tons of folks would call-in to inquire on orders ) this got farmed out to "warm bodies". Kind of like an emergency phone-tree where smaller set of folks invoke a bigger set to get the word out faster.
Apple probably has telesales folks who are Apple employees, but not a large number of those folks. Given the likely influx of nervous buyers calling in they were likely swamped. If massively swamp would not be surprising it this got farmed out into the 1st tier support queues to do in their "spare time".
You drunk?