Question: Re-issue chains & Bijoux chains

[Farkvam]

Hi there! I just bought and received this bag, but as it’s so old, the serial number sticker was no longer attached. I got it authenticated prior to purchasing, but one things still gives me pause: it does not have the “secret zipper compartment.” I read a similar post on another forum, but I’m wondering if it’s highly unusual to have an older vintage double flap Chanel that in fact does not have the zipper compartment?

I have one of these with the zipper compartment, but there were variations WITHOUT it. Here's one being listed now in Canada:

CHANEL Classic Lambskin Double Chain Double Flap Bag Black Medium Square gold hardware - Preloved Lux Canada AUthentic.

We guarantee this is an authentic CHANEL handbag or 100% of your money back. This Chanel bag is crafted in black lambskin leather and paired with a gold bijoux chain. It is similar size to a classic medium flap. This is a very unique vintage bag that there are not a lot in the market at this...

www.prelovedlux.com

PS The seller also uses the term bijoux chain here, as well as reputable authenticators, but I would call it a reissue or mademoiselle chain personally.