Yes and no. If they are human, they cant be slaves and should all be counted.
If they are not human, then none of them should have been counted.
And there it is isnt it?
The south. In their wisdom, shot themselves right smack in their own foot.
It had nothing to do with their worth or lack of it as human beings. It was the non-slave North that wanted less than full credit to be given to the South for their slave population. The South wanted slaves counted fully as much as all other citizens which would have given them more Congressional seats. It was this three-fifths compromise between fully counting them, favored by the South, and not counting them at all, favored by the North, that allowed the Constitution to be ratified. The damnable lie that it was a reflection on a slaves worth as a human being has been pushed in government schools for three generations.