it looks like all they check is the OBDII to ensure the cats are working properly
http://www.dmv.com/nc/north-carolina/emissions-testing
EMISSIONS TEST FAILURES
If your vehicle fails the emissions test/OBD (On Board Diagnostic), within four months, you must have the vehicle repaired, after which it must pass the after repairs emissions test. The vehicle can be repaired at the station or elsewhere. A $250 civil penalty is levied if this is not followed and the vehicle is not permitted to renew registration.
so if you have LT's and don't have the CEL tuned out then you will fail.
hope that helps