INEX rules are that in 2011 you can run BFG's, American Racers, or Federals on dirt.
Your club or track can change rules to be more strict, but not more lenient.
Example: Beaver Dam mandates door padding, though INEX only recommends it.
If the guys running your series say you have to run certain tires, they can make that choice, as long as it is one of the tires legal under INEX