These shields as everyone can agree, contain tons of controversy. To me, I believe that these if they are period pieces are much like the WW1 trench art, or the over-sized constructed KC for U-boat crews. They are of course, quite desirable. It would be interesting to see if there was a test to see when the metal was formed. Sort of like a C.S.I Militaria deal.
In today's world of fakes and forgeries, I am always and will always remain skeptical until, some other proof can be obtained.
Both Michael and Peter's examples shared do look convincing though...
Regards,
2dresq