I've heard the same and I've speculated of even a prototype being out there. Sadly the book doesn't state if the badge is real or not, as it only tells the story of the Winter War in short and what the badge is made out of. The text states that the badge was never issued, so I believe there to only be a prototype or two and I believe the badge in this to be a real one, but I cant say for sure. All badges in the book are original pieces, but missing ones have a graphical copy, as they are so rare that they cant be found.
Personally I believe an original prototype badge to be way over 10,000 dollars, if there is indeed one.