Can update us if your sistee decide to buy from ioffer? I am not sure how much their price for selma nowadays but yes I also saw such bags wrapped in plastic but look very similar to authentic ones.. Not sure about weight and other details though eg: zipper, stitching, etc..
I know there are sellers here in Australia on eBay, they have over 800 positive feedback, their bags look 100% authentic, but are not. Every little detail is the same, so much that I kept my selma next to the enlarged pictures of theirs and I couldn't find one tiny detail that was different. But I could tell from the wrapping and the dustbag that it's not authentic. All they sell is mk, and all these buyers have left feedback thinking they bought the real thing.