By now you already have the correct answer: only handguns have to be registered when moving to CA.
If you are late, just send in the form and the fee. While I have not tried this myself, I highly doubt there will be any consequences. It would discourage people from registering.
Here a good thread on calguns:
http://www.calguns.net/calgunforum/showthread.php?p=2697239
Hope this helps,
George