A mostly useless law.
As a person who has had their converter stolen three times, I have researched this issue.
Thieves are not taking catalytic converters to resell them. They are breaking them down for the constituent rare elements such as palladium that are inside, which they then sell, and then they throw away the rest. So passing a law to prevent resale of stolen converters won't help anything.
This is likely an example of our government wanting credit for appearing responsive, but actually being too stupid to do anything meaningful, like give more money to law enforcement so that they can break up the organized crime that's rife in the Central Valley and who are using these thefts to fund themselves.