The IRS usually wants some kind of form from the Probate Court showing that you have been accepted as the administratrix. They want it to have your signature on it, too (I mention that only because my own county doesn't have any such paperwork!). I would also fill out a Form 56 (Change in Fiduciary) and carry it to my nearest IRS office with some ID.
Considering that it is part of the Adminstrator's / Executor's job to make sure all taxes have been paid, the IRS makes inquiring difficult!


