Possible House key for Joseph Priestley House in Northumberland PA

BELOW: Box Lock and Key surviving from Fair Hill, home of Joseph Priestley 1780-1791. The house was destroyed during the Birmingham Riots of 1791. Now located at Priestley House, Northumberland, PA.

BELOW: Box Lock Key from Priestley House, Northumberland, PA presumed to be Joseph Priestley's key to his home (Priestley House)

(photo supplied by Andra Bashore, Historic Site Administrator, Priestley House, Northumberland, PA)

BELOW: Photos of a key I recently acquired.

A Skeleton key allegedly from Priestley House, Northumberland PA

I have found a piece of potential Priestley memorabilia and would like to discuss the likelihood of its authenticity with anyone who might be able to help me.

I recently purchased a skeleton key from a woman in Lewisbury, PA who says she purchased it from an estate sale in Dillsburg, PA.  Both of these locations are close enough to the Joseph Priestley House in Northumberland, PA to make me think there may be some truth to the story.  The very old paper tag wrapped around the key says that the key was the house key to the home of Joseph Priestley built in 1795-97 in Northumberland. The ink on the tag looks like from an old fashioned quill ink pen. The key itself appears to be made of solid brass and is quite heavy, measuring 6 1/2 inches in length and weighing about 8oz.  I have poked around a little and found that the lock and key for his former home in Birmingham is located at Priestley House in Northumberland (see photo above). From the picture of those items it is clear that the key I have doesn't appear to be the same as that one, and it shouldn't be.

Does anyone know if the original key or lock for the Priestley House in Northumberland still extant? Do you know anything that would be able to assist me in my determining if this is, in fact, the real original period key to the Priestley House? I have already gotten a response to an inquiry to the Priestley House.  They have supplied one of the photos above labelled "Box Lock Key from Priestley House Northumberland, PA"  

Any additional information will be appreciated.