I just picked up a used MT10 BD1. I noticed the holes have odd drill markings where it looks like the bit went in. Would this make it a second? Is this normal or considered unusual?
I used to work in the sheetmetal industry, we would put these sort of 'notches' in laser cut holes as locators. i.e something that would go in the hole( a button or switch) would have a locating lug which would stop the thing free spinning in the hole by slotting into the notch.
Not sure if it's related, just interesting seeing the exact same thing on a knife.
A decent number of my Mules have been like that and I have at least one of each so far. I don't recall which ones off hand, but it's what I refer to as a "manufacturing artifact".