You never cease to amaze Charmy.
As a journeyman toolmaker, I think it is entirely possible the theory Tom described. I have been spotting dies on several occasions when a punch, core pin, or gib has fallen...and it never drops straight or head on. It always damages the cavity or botom half of the shoe/mold.
Ricks idea is possible, but I tend to agree that the mint had the proper equiptment to test the rockwell C scale hardness, even back then. Unless a shoddy worker was in a hurry or neglected proper protocol, that most likely would not happen.
Back to the coin. Incredible.
