You can get help with any tech problems on any device, regardless of where you bought it. I have never been asked to provide receipts or serial numbers for any of my phones or computers.
The only time ownership, date of purchase, etc. come into play is when you request a replacement or repair of something under warranty.
As for iTunes 11... I'll believe it when I see it.
I'm sure the management shakeup did no favours to its development, and I wouldn't be surprised to see it pushed back to December.
EDIT: You were right, it's
out now.