If you claim that the best way of interpreting the Constitution is intrinsically the way the Founding Fathers meant it, it's not fallacious.
Appeal to Tradition, no?
No, it's not an Appeal to Tradition if one can point to evidence that what you claim to be their interpretation actually was their interpretation. If you're taking one's own views and ascribing them to the Founders without proof, then it would be, or if one were to assert that the Constitution they wrote was the best of all possible Constitutions for all time.