The Calif Assault gun ban was passed so assault weapons had to be registered by Dec 31, 1990. I'm guessing your mags are not Calif legal. It's also my understanding, that no matter when they were mfg, it is illegal to import high cap mags to Calif now.
Could be wrong about that, but that's what I seem to remember. Even though the fed ban was lifted on high caps, Calif is still a "high cap free" zone. You can't even mail order a 7 round 1911 mag if you live in Napa County ( I have a friend there). They're still catching guys who buy mags at the Reno gun show and try and drive back home to Calif.
Navy Vet & SWIFT Boat OIC