Yes, this is the permanent setup on exiting the airport now.

Leaving Hourly Parking, or driving away from the terminal, the 2 left lanes are marked for "I-495" (and, yes, they have plenty of room on the overhead signs to add "NO TOLL"). The right lanes are marked for Route 28 (and if you don't get onto Route 28, or make a left-lane exit, from these lanes you will get to the toll plaza).

Exiting from other parts of the airport (specifically Economy parking and rental car lots), you are initially led onto the right lanes mentioned above. But there are TWO left-lane crossovers from that roadway onto the "I-495" roadway (a.k.a. the toll-free Dulles Access Road).

There is a good, updated diagram at http://mwaa.com/_/file/_/northroads2008.pdf