The h-pipe that comes on your car is catted. Are you talking about aftermarket catted h-pipes? Off road h-pipes are the illegal ones. I run off-road pipes.
This is such a grey area its not a simple yes or no. Yes they will pass emissions, but it is illegal to change cats on a car unless the stock ones are worn out. It is also illegal to reduce thn number of catst on a car, the stock pipe has 4 and aftermarket ones have 2. But most shops will not fail you for an aftermarket pipe, but they can. An aftermarket pipe with 2 cats will also make the car louder, and they can fail you for this too.