The V band clamps are just generic stainless 2.5" builder parts.
The Cat is not the stock unit, its a stainless Magnaflow unit that was put on years ago. The old 3FE exhaust was gutted and a single, inside the frame rail 2.5" stainless exhaust was built. We just built to the cat because the rest of the exhaust was already 2.5" and in good shape.
Technically no, the truck is not emissions compliant. It is being registered as a "Historic" vehicle in MD. Here in VA it would be registered as an "Antique". It would be a fitment nightmare to fit 4 cats on the thing to make it compliant to the GM engine. Doable, yes! Fun, no!