I've seen older packaging at the Posh Peasant on clearance for maybe $50 (?) I don't remember, but it was a steep discount (they don't carry the line any more). So, no, it would not be out of the ordinary to encounter this kind of price on KM. I don't think someone would bother faking these scents -- they are not widely known (outside of BN of course!) and their appeal is limited.
I would request that they post a picture of the actual bottle/packaging; I don't like stock photos like these -- you don't know what you'd be getting. That would be my concern.
You can also ask them what the source of the bottles are.