Obverse 5 does not always display the flaw in the forehead, however every obverse 5 I have seen has the scalloped top center leaf, whereas I have never seen that top center scalloped leaf on any other obverse than on an obverse 5.
I would not necessarily use the die crack above the R as a determinant, however I believe that there is enough other evidence to confirm the obverse as an obverse 6.