I just bought this through a webpage named trendsales, the seller is Ditte Halleskov aka. Deedee - anyways there a no picture of the ID number and the picture of the stamp/engraving inside is a bit unclear.
She claims its authentic - and has over 500 good reviews selling primarily second hand chanel bags but also other brands.
The tread is in the Chanel forum and all questions goes into the same thread. I'm not sure they would authenticate this in danish and perhaps missing pics, but you could give it a try. You could always post more detailed pics when you gets it.