Yeah I'd be amazed if it's a hoax. It screams TakTom MP design. FansToys did debut their own Masterpiece Cliffjumper around the time these pics debuted, but they're clearly very different, and it's very clear which is FansToys's style and which one really does appear to be perfectly done in the vein of an official MP. It's simply too good. And the idea that no 3rd party group would come forward and claim this sculpt that has more interest than FansToys, considered the king of third-party Masterpieces, is absurd, really.
This really is a case of hearing hooves and advising you not to think zebras first. It simply has to be legit, or I'll eat a hat.