That could be shadow on Paul's first example? If not, and you're right, Rob, then surely that would rule out accidental damage, as the 1900 example would've required the missing part of the die to partially repair itself, for want of a better word? Just to really mix it up, could the different sloping mouths (if it's not a shadow) make for three intentional reverse dies? No tongue, down-sloping tongue, up-sloping tongue? Or should I say, matrix?