I totally agree -- this is really rather silly, and all that;s happening here is a bunch of "archeologists" are trying to justify further funding.
Here's my proof -- probate records were extremely accurate in those days, and a probate record will typically list every piece of property (furniture, clothing, utensils) on a room-by-room basis. The slaves will be listed as part of that property.
I've seen the records, and they are publically accessible.
So why would someone try to 'figure out' history from little broken chards in the ground, when a FULL WRITTEN RECORD already EXISTS?
It's because various statutes require archeological digs/ surveys be done on certain sites as part of the price of getting building permits, etc. So an archeology industry of this sort grew to suck up the available $$, and stories like this are created to justify the ongoing existence of such requirements.