I think your question is completely legitimate. I remember reading a thread earlier this year on tPF about a PFer who got a fake bag from ordering from one of the department store websites. It's not that the store carries fakes, but it's possible that a customer pulled a bait-and-switch on the store and returned a fake. If you do a search in the tPF, I'm sure you'll be able to find that thread. If you ever have doubts, you should ask, no matter where you got it from...unless it was the actual designer's boutique.
Also, fakes aren't all terrible quality anymore. There are some ridiculously good fakes out there that even boutique SA's have a hard time telling apart from the authentic bags. Be careful!
That being said, it sounds like other PFers have this bag with the same hardware, so enjoy your bag and CONGRATS on the beautiful bag and great deal!!!!!!!!! YAY!!!!!!!!!!!!!!