On his facebook page when someone asked, Hallet says "I swear I'm not being intentionally vague, but Im not sure what made the final cut. Sorry man".
So can we infer then that his design above *was* built, and filmed, but he doesn't know it's actually in or not? Rather than not knowing if it was even created by the creature team. Or maybe he doesn't know if it has been used in CGI.
At the very least it sounds like he thinks it might be in ...