probably not the same sally, but you can always do a doccument check at your local court house and see if there was ever a sally at the property (living on the site) or do a lineage check and see if there was anyone attatched to your family with the name.
There could be other problems, depending on where you live, you could contact ghost hunters in your area and see if they would do a ghost hunt on your house, it's possible they could come up with some evidence. Otherwise, I suggest keeping an open mind and asking Miss Sally what she wants. Usually ghosts want to relay messages, if she wants to cause harm, you do not have a ghost, you have another form of haunting and you want to get the heck out.