If it's a fake knock-off replica imitation phony but it's as nicely made and finished as well as the real thing, does it matter?
Years ago I was selling a Daytona that had no box, and struggled to get a "real" one off of eBay. I determined that it was real because of the age and condition, figuring that any fake would look new and pristine. In the end, I don't know why these things are so important.
Now... the Omega boxes, most of those are made of wood and really quite lovely, especially for the Speedmaster and some limited editions.