Vehicles must follow the below schedule for compliance based on engine year. If their engine is older than the schedule allows, they must replace it or they will not be able to register with the DMV or transfer ownership.
Below is the Engine and Model year restriction by Truck Class as of Jan 1, 2020:
Vehicles weighing more than 26,000 pounds –
Vehicles weighing 14,000-26,000 pounds –
Most important thing to look at – Has it been signed off on/check off that it qualifies?
Important to note: these reports may vary between dealerships, but they all look at the same general attributes.