Wobbly stitching to me isn't really proof that something's fake unless it's so bad that it just screams it. Something like an inside pocket is a different matter since the same templates were used on all bags of the same style and same time period, it's not the kind of thing where someone could have simply made a mistake. See the pics I just added from your seller's listing and compare them to other Duffle Sacs on Ebay.
Here's a listing for another red one from 1997, notice the smaller pocket, and also the much better-matched color of the zipper that you pointed out in your first post.
http://www.ebay.com/itm/Vintage-Coa...D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557
BTW, the same bag you bought on Etsy apparently was also listed on Ebay. The bottom seam looks ok. The pics of the inside pocket aren't wide enough for a size comparison with the known genuine bags though.
http://www.ebay.com/itm/COACH-xl-Du...D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557
More opinions are welcome.