I think it is important to keep all options on the table, even the improbable. When you already have 8/2, 8/3, 8/6 and 8/7 as accepted variants, there is nothing to exclude the possibility of 8/4 and 8/5 also coming into the equation. At a time when they were clearly reusing every available die, it is also not inconceivable that an 1840s obverse could have been repurposed if they found one.
Probably not relevant if all they wanted to keep was an example of the ww and no ww dies, but FWIW Hocking only lists the 18- die and an 1859.