Hmm...12 Series makes more sense as that was the last series with the hallmark by the time it got to 13xxxxxx, Chanel had changed the hardware. As far as price, really you need to go by condition, inclusions (card, box, etc.). As these days even vintage prices have gone quite high. I will say the thing that concerns me is she could be mixing pictures. Why did she say 16 and then 12 series when questioned? Is she a "regular" reseller or normally trusted site? If you wish to proceed, make sure she gives you all pictures that you would need for authentication, and post in the authenticate this thread. Make sure you check reviews for the seller etc. AND MOST IMPORTANT- DO NOT PAY BY WIRE TRANSFER or PP Balance. Only PP Invoiced with CC, or you will have no protection.