that bag is 100% fake! stay away from ioffer if you're after anything authentic.
also, you should be posting this in the "authenticate this chanel" thread, which is in the Chanel Shopping sub-forum.
if you're after an authentic bag, why not try browsing the "authentic chanel finds" thread? That too, is in the Chanel shopping sub-forum.
Hope u find something nice for your gf! =)