The new third-generation Chromecast dongle device was supposed to be announced on Oct 9 at Google's Pixel 3 event, but surprise! Best Buy accidentally set it out 10 days early and sold it to some customers under the old Chromecast SKU (store keeping unit) at the same price.
One customer that brought the device home was a redditor under the username GroveStreetHomie who uploaded a photograph of the previous generation Chromecast (gloss finish) beside the recently purchased one (matte finish) captioned, "I think I bought the 3rd gen Chromecast too early."