Yes, actually I was wondering that too.....you can find the code on the bottom of the bottle........its 4 character long im pretty sure....letters and numbers
the numbers are not on the bottom......it's etched on the back on the glass....you'll need a magnifying glass or jewelers loupe to see it and good light.
I just auctioned off a bottle of Chanel....if you think it's not authentic you can google how to spot a fake bottle Chanel. The only way to tell with this bottle though is by the sprayer tube since you can't see anything else on the bottle and the lid and the clarity of the glass on the bottle.