ITA regarding buying it at the outlets to save yourself the hassle, but i know how hard that can be if you don't live anywhere near an outlet. the best tips i can give you other than posting it to be authenticated here on TPF would be to keep an eye out on what's ACTUALLY in the outlets right now. lots of girls post about their outlet hauls, and inevitably we get suckered into buying the keychains so you're bound to see people post pictures of their most recent keychain purchases. (they HAVE to put the keychains RIGHT by the registers for a reason right?! "Yay ringing up my purchases...oh look at this it's so cute! only $16?! to buy or not to buy...oh what the hell *grabs 2*").
not that this is a guarantee, but it makes more sense that sellers would be selling more current items. but like i said: this does NOT NOT NOT mean it's necessarily authentic.