A while back one of my friends was at the Hermes store in Vancouver and she saw a 30cm Crocodile Birkin in the window and told her SA that she wanted it. SA told her that it was display only but she wasn't going to take NO for an answer and said that she wouldn't leave without the bag. (she is a loyal customer at Hermes, with 4 birkins and 3 Kelly bags) The SA finally gave in and sold it to her so anything you see in the store is for sale.
Wow! I'm not sure if certain displays are the same in Paris as in the US or Vancouver, but in Paris I was told that some displays were demo models and not made up to the normal standards as the bags for sale.