I remember a topic about the Thumb notch that got quite heated.
You could be right on about that, and that would make since that the blade would be shortened to accommodate the removal of the top of the notch.
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"Political correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end."

RKCC #502