Does a good counterfeit Apple Watch actually do everything a real watch does, e.g., respond like a genuine watch after you install an arbitrary app on it and start using the app?
(If so, I'm guessing they made the cheapest genuine Apple Watch look on the outside like a more expensive one.)
It won’t, but a random person off the street might not immediately notice the difference, particularly if they’d never used one before.
Even booting it to software, it might be enough for a completely-untrained person to assume it was real. Actually pairing it with a test phone might be the easiest/fastest to be certain.
(If so, I'm guessing they made the cheapest genuine Apple Watch look on the outside like a more expensive one.)