Many times tapered wings will be flat across the top surface yet are said to have no dihedral when in fact, that would be a slight bit of dihedral. This is done to prevent the illusion of a drooped wing or anhedral when flying. Was very common in the old pattern days and had very little effect on how the plane flew. But it sure made the airplane more pleasant to look at in some flight attitudes .... especially landing. Many airplanes still do flat wings that same way today.