No muddypaws I am not saying you don't know what your doing. Nor am I saying that no one else does not know what they are doing.
Just that I know for fact that if you bought a 99-02 Ford Powerstroke 7.3L Truck in Michigan you will not find a cat on it unless it is four legged and fury.
But if you bought the same truck in Cali it will have a cat on it. All depends on where the truck orginated from. As some states have laws that require them to have cats and other states do not.
Although now as of 2004 all diesels are emission regulated by the Federal Government and now all new diesel trucks have cats on them from the factory.