If it is written the same as the previous ban. (Which it probably wouldn't be). Stripped lowers will still be post ban if assembled after the date the ban was enacted.
The lower receiver would have had to have been an "assault weapon" at the time the ban was enacted.
So unless it was assembled and attached to an upper with the "bad" features, it wouldn't count.
But I wouldn't count on that in the future. The last bill put forth was even more restrictive than the 1994 ban.
I am no longer participating in gun forums.