Originally Posted by
RoadGuy
Probably part of a wheel retension system that includes a washer with a lug on it that fits into the hole to keep the wheel from dropping out/off if the quick release fails or the wheel nuts loosen.
Yep, from what I recall of my department store bikes in the 70's and 80's, they all had those holes for a retention washer, exactly as you describe. The forks survived all of the abuse that a young teenager could dish out. :-)