yea bob they are only on the right for the blind spot as previously said .i drove a gmc general awhile back that had the window on the right and a vent door on the left,as for the kw's and the petes that window was there before someone decided to add the convex mirror's to the nose of the trucks for your blind spots.surprising my real 85 kenworth w900b does not have that window on the passenger door...its solid
