If you are talking about having a CARB number or something like that, then most of the brand named hi-flows don't have one. They may say its smog legal but they don't give any documentaion to prove it.
But, there is hope... One brand called Morflow makes a set and they have a CARB number to go with it. I think you'll have to order it from them if they are still in business. Try searching for them on the web. I think its
http://morflow.com/.