Odds are that you won't encounter any fake Pixel 3s or Home Hubs, and if you're reading this site, you'd probably be able to identify a counterfeit Google product pretty easily. But if you're buying a piece of Google hardware off, say, Craigslist, and you want to verify its authenticity, the company's 2018 products each come with a reflective anti-counterfeiting sticker that'll let you know what's real and what isn't.
left: The sticker head-on. right: The sticker at an angle.
Support pages dedicated to reporting fake Google products were added back in July, but this "guide" to identify real vs fake items is new. Basically, if you're looking at a 2018 Google product and want to make sure it's legitimate, just look for a reflective 'G' sticker somewhere on the box. It'll appear silver when looked at head-on, but it'll turn multi-colored if you have a look at an angle. This sticker isn't easy to peel off, and it'll be pretty obvious that something's wrong if you see one with marks on a corner.
Google says that all of its 2018 products have this label. My Pixel 3 XL's box has it, and it's also visible on photos of the "revised" Chromecast's box. So if you were ever worried about ending up with a fake Google item, you can rest easy now - at least until the counterfeiters figure out how to replicate this sticker.
- Google Store Help