It's possible, but short of verifying the product authenticity code, inspection alone may not be sufficient. It's like
batteries. In a sketchy gas station or convenience store those Duracells are frequently fakes. OK if it's an emergency if you need a AA right NOW, but otherwise something I never buy there. Bottom line is if it tastes crappy, regardless of authentic or not, it tastes crappy and I'd be looking to replace them with stock from somewhere other than that same store.
I do wonder if with all the new regs relating to pod sales in non-vape shops if small stores did simply find third party sources to maintain price margins and avoid any paperwork and hassle in stocking Juul pods obtained directly from the manufacturer. Let's face it, knocking off a pod isn't terribly difficult for an overseas no name manufacturer.