Mount Vernon rye had nothing whatever to do with George Washington.
It's named that because Mount Vernon is (or at least was) a very desirable section of Baltimore with which the brand wished their customers to relate it. The Hannis distillery (which made the original Mount Vernon) was located fairly close to Mount Vernon (Baltimore), although the company was actually located in Philadelphia and used the Hannis distillery as contract distillers for the brand.
Ambibay: see more information here
http://ellenjaye.com/mountvernon.htm about Mount Vernon (which I've always seen in a square bottle) and Mt. Vernon (which did come in a round bottle, but would have been WAY older than what Chuck has in mind). If THAT's the one you have (note the abbreviated "Mt.", not "Mount") -- PLEASE let us know -- and take photos!!