Robert,
This is a good first step but does not address the reason many vehicles have been registered this way.
Most of these "Replica" vehicles cannot be registered for road use with just an SPCN registration due to the smog requirements being based on the engine block if they do not have an SB100 #.
As you know there are only 500 SB100 #'s issued per year and that is not nearly enough.
I think it would be a much better solution to offer them an SB100 exemption (outside of the 500/yr limit) along with the SPCN registration if they use the application for amnesty and will not pass the current testing requirements.
I think this alone would be encouragement enough to get most of them to join in the process, thereby getting the state caught up on revenue that is due them.
Because this bill does require the car to go to a referee to determine if it is subject to smog testing requirements, they could make that determination and provide them as needed.
Glad I got my SB100# when I did.