BB, ThaNKS! I only heard the rumor part of that notch but the truthful part seems more valid.
The rumor part that we were familiar with was, "the notch was for inserting in the teeth followed with a kick to the jaw to make it stick ... so that the medics who followed a short way behind could identify the deseased."
But I'm not sure that they were all deceased! Not yet anyway!
That rumor wasn't as bad nor as sick as the decapitated bodies on the highway movies that we had to watch every Friday before liberty was granted. And those films were usually followed by the gonnoria and syphilus flicks (spelling?) that were intended to keep us out of the whore-houses outside of most military bases.
Thanks again, BB.