You usually can just pick these up if you make an appointment at the Genius bar. Heck often they will even do the install for you.
http://support.apple.com/en-ca/HT202450 - they specifically state to call them so I'm a bit surprised that you need to "pay for an incident ticket"... the fact that your paying for parts should supersede that.
I made a Genius Bar appt for next week since that was the earliest available. The guy I spoke to said it will cost $10 per foot, but I have often gotten incorrect info, so I'll see what happens when I get there. Would it make sense to get all 4 replaced, or just the broken one?
Regard speaking with AppleCare for ordering a part...since the automated system asked me if I wanted to buy credits even before transferring me, I was concerned I would be charged regardless of the nature of the call. If I accept the charge at the time of responding to the machine, would they simply not charge anything if the call just involved an order?