I suspect the AirNav stuff is identical to the "real" charts,

They *are* the real charts. Airnav links to the NACO website for the
PDF files. They were just lagged a bit in updating the links to the
updated cycle on NACO during the last few days.

Whether a chart is current or not has *nothing* to do with the dates
printed on the edge of NACO chart. Each chart has a serial number
printed at the lower left hand.
(http://www.naco.faa.gov/d-tpp/0613/00142IL16R.PDF for example, has
"Amdt20 06103"). It means the chart is last revisioned on the 130th
day of 2006. As long as the most recent chart on NACO has the same
serial number you chart is still current. It doesn't matter if you
printed it out 3 years ago.