Beerslurpy and Standing Wolf,
Actually I think the way the section is written it is a felony to use an unregisterd weapon. I believe it still stays a misdemeanor for carrying it without a permit.
There is no firearm registration requirement in California except for assault weapon owners and personal handgun importers. However, you may submit a Firearm Ownership Record to the DOJ for any firearm you own. Having a Firearm Ownership Record on file with the DOJ may help in the return of your firearm if it is lost or stolen. With very few and specific exceptions, all firearm transactions must be conducted through a firearms dealer.
However, from DOJ's FAQ
I am moving into California and I own several handguns. What are the new-resident registration requirements?
You are considered to be a personal handgun importer as defined by California law. You may bring all of your otherwise California-legal firearms with you, but you must report all of your handguns to the DOJ within 60 days as required utilizing the New Resident Handgun Ownership Report. You are not required to report rifles or shotguns. You may not bring ammunition feeding devices with a capacity greater than ten rounds, machineguns, or assault weapons into California. (PC sections 12001(n), 12072(f)(2))
However there is a law that charges you with a felony for using a non-registered hand illegally. That might apply to carrying without a permit and probably will apply to defending youself unless it's a squeaky clean use.
So you could conceivebly commit a crime, felony, for defending yourself with a firearm you had when you moved into the state 25 years ago before the above sections were enrolled.
To obtain a list of firearms listed in your name, send a letter requesting this information to the Automated Firearms Unit, P.O. Box 820200, Sacramento, CA 94203-0200. The letter must be signed, notarized, and include a photocopy of your photo ID card (ie., driver's license or DMV ID).
I an not, nor do I play, a lawyer so this info is worth what you paid for it.
Tom