There are two ways to set the points. One is with a feeler gauge (.020" at widest opening). Second method is with a timing fixture. That is what the marks on the mag plate are for.
But if you are speaking of the two marks on the brass cam plate, those are for synchronizing the spark with the opening of the carburetor throttle shaft. With the two marks aligned with the pointer (nearby in your picture), the carb should just barely be about to start opening.
