If you can feel the spots and this is on a machine without a wet clutch, as that is the area is where the primary first makes contact with the belt and as such any ill-regularizes will quickly takes it's toll on the belt ..yeah, if you can measure or feel the spots and yours is one without the wet clutch I would replace it. Otherwise it may only be something to do with manufacturing or not enough to worry about. Might check the belt alignment. One question- do both sheaves have the same marks in the same place?