I fully believe that the vents were intended to be an exhaust port of somekind, rather than an intake for air. BUT..................
there are several companies out there that are making kits for the pass. side vent to bring air into the airbox on the 2008 models (IIRC, that is where the airfilter is at on the 6.4), as far as the 6.0 or 7.3 trucks, unless you can route a bunch of pipe to draw in air to the filter, the badges are purely cosmetic.
Having said all that, I did notice in one off the Diesel Mags, that Airaid has a new univeral air intake kit, so that you can basically design your own custom intake.
Looks pretty neat and could really open a whole new world for ZooDad mod.
Airaid Univeral Air Intake Kit