Looks questionable to me but I'm by no means an expert. It's not just dirt near the barcode though, you can see wear on the cover artwork on the bottom of the spine as well as on the front under the ESRB rating. Maybe even some dirt to the cover artwork on the top left hand corner on the back as well, hard to tell from the photos though.
There's quite a few places that can make convincing looking Y folds now a days. There's a seller on Mercari who's been pumping out Y fold resealed copies of popular 1st party Wii titles, including this title, for months now.