Something deeply ironic about emissions inspections in my state: my diesel VW is exempt from them. Some shops might do a cursory look to be sure you haven't deleted the particulate filter or the catalytic converter, but, really, most just make sure there is a pipe running from the exhaust manifold to the rear of the vehicle.

Last summer, I accompanied my son when he went across the state line to purchase a truck from a private seller. Said state has no inspection requirements. One of the seller's other trucks was a diesel conversion, and the exhaust was just routed up through the bonnet. Definitely no cat on that vehicle!