There was a documentary on the Thor BD on how they made the hammer (a few of them, actually, of varying weights depending on the scene they were being used for). None of them, of course, were solid metal. What surprises me is that they bothered to add the CG shield to a blooper, but then again, it wouldn't be the first time.
Either I made up lies about the Boston Bomber or I fell for someone else's crap. Either way, I have absolutely no credibility and you should never pay any attention to anything I say, no matter what the context. Perm me if I claim to be an insider