I have a fork off an old Ross road bike and the "keeper" on the bottom of the dropout is quite different from the modern "lawyer lip" flanges, it makes the dropout into a C shape which I assume is to keep the wheel in. I also have a Mead Ranger from the 'teens, (like Sheldons) that has no dropouts. While much 'safer' it is much harder to remove wheel (bend fork leg out) and to adjust (bend again). Good idea to check wheel nuts or skewers often, like before every ride.
and yes, after repairs on my truck I always check wheelnuts after the garage returns it.