I stand corrected...
So the question is then, do you as a California LEO have access to NJ DMV records (via dispatch or otherwise)? And if that is the case, and even if the officer were to testify (in this case) that he had done so, the fact that the OP's vehicle registration was valid, would suggest that there was really no justifiable reason for the stop!
Not sure why but this thread reminded me of this:
http://www.chp.ca.gov/pdf/media/09-10.pdf
(No disrespect intended towards the OP with the "Cheaters" reference).

