The funny thing about that is the game store I really like also sells fake cartridges/ROM hack cartridges that are clearly fake and not labeled as the real deal. Don't know how they source them, but I could probably buy something like Shadow the Hedgehog on Genesis.

Also, I really don't expect anything even slightly good to come of this GameStop retro games thing considering the fact it doesn't matter whether the game is legit or rare, they'll buy at as low of a price as possible then sell at least 2x the going rate online. That, and their workers probably aren't gonna be given any training whatsoever to spot even the most obvious fakes and will probably get severely reprimanded over buying a fake.