This Mary Winslow is not mentioned in the will of Benjamin Winslow of Anson and Rowan County, NC. See here: https://images.findagrave.com/photos/2015/362/156289009_1451437282.jpg
The only children that can be definitely imputed to this Benjamin Winslow [Winsley] are:
Daughter married to John McConnell
Daughter married to Samuel Wilson
Daughter married to Patrick Hamilton
Daughter married to Hance McWhorter
Son Moses
Son Benjamin
If you can post the text of the will that refers to Mary Osborne Wilson, perhaps we can straighten this out.