Could easily have been.
Even though, as far as I know, the overall pedal design from 68 to 75 was identical, it’s not unusual to see variations on a theme. Including holes, no holes, holes in different places, paint, coatings on one, and not another, or paint up to a certain point on one and a different point on others, spring tabs bent different etc.
The big car manufacturers have different vendors and sometimes those different vendors become different vendors or make a slight machine change or whatever.
So yeah, you could have a stock pedal with a hole in it one year and not the next, or one month and not the next. Even though nothing changed except the holes.
So, at least for me anyway, I wouldn’t find a small change like that unusual or unexpected. Especially if it gets in the way of progress! That’s completely normal with these old silly rigs of ours.
I don’t think there’s any way for us to know without looking at each and every year multiple times.