That edge of the trigger guard bow itself looks filed on a bit,,maybe just the lighting in the picture, but it looks like it's been taken down just a little.
The thin edge of the Colt trigger guard is gone and is kind of blunt and rounded there where the marks are.
It looks like there are file marks accross that rounded edge of the guard as well.
The 5 marks in question do look unevenly spaced or of even depth.
They too look to have been done w/a file from the marks in them.
Maybe the marks were serrations of sort for a better 2 handed grip.
Perhaps there were many more of them to begin with & closely spaced.
When (if!) someone removed most of it by filing them off,,it left the guard edge a touch rounded and only the remnants of the few deepest serrations left behind and a few light file marks in the steel remaining.
I see a lot of hunting rifles with notches or even punch marks for what I take it to be deer hunting successes. Every once in a while a handgun with grip notches, but most figure it's done as a price enhancement to catch someone that's gullible,,you know the old 'this was Jessie James' Colt 45 Auto,,see it has his initials inside the plastic grips too.'
Just my thoughts.
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