Bud, it's not much of a "fingerprint:" in those states which maintain a database of fired brass and bullets, it's never solved a single crime. If both the gun and bullets and/or fired brass are in the hands of investigators, it is usually possible to establish if the gun fired the rounds in question -- but not always.
"Microstamping" fired brass isn't all that easy, as the brass has to be sufficiently ductile to take the impression but not so soft that the mark is easily lost or distorted afterwards. I don't know if the firing pin trick would work well enough satisify the CA law, but even if it does, it won't keep bad guys from getting the same kind of used, underground-economy guns they've been using all along. Nor will it slow down the clever fiend who knows how to swap out a firing pin. It's hardly rocket science, especially in any gun using the retention method found in the 1911. Might even be able to file off the marks without making the pin too short to work.
Or, hey, the bad guys could just get a revolver. They're not included in the microstamping requirement! Funny, both times I was held up at gunpoint, the malefactor(s) used revolvers.
Other methods seem to be implied in the excepts posted by Redhawk. A stamp set into the breech face runs up against the same limits as the firing pin version and while maybe one couldn't file it away, the Dremel is a well-known tool for removing unwanted excresences in tight corners.
The same quotes also have the genius behind this marvelous development speaking of "stamping bullets," presumeably as the gun is fired. Since he couldn't possibly be the sort of moron who doesn't know the difference between "cartridge" and "bullet," he must be speaking of some simply astonishingly super-duper technology that will fit in the barrel of a handgun, mark a movin' bullet, and never, ever suffer catastrophic failure. They do get the Sci-Fi Channel in CA, don't they?
As Rich says, it amounts to a ban on any new semiautomatic guns in California. And probably a ban on any of the ones already there changing hands in a legal manner. Did The Governator pass up a chance to veto this already? If not, let's hope for a lucky coin-toss and that he ignores anything his spouse has to say about it.