Pretty sure it is and Cali even still gets some nice “trims” unique to them. I mentioned the USPc as well as that is definitely still in production and Cali legal.
I must have glossed over the PX4, again hammer fired like was said, but an excellent polymer gun.
I still think that if you want a poly striker get a Gen 3 Glock. The slide release is either easily trained around or replaced with a factory part. This gives you EXACTLY what you want with the small exception that you will need to install or have installed a factory part. You will probably need to install night sights anyway.
But again if you want a specific type of slide release you have pretty much the following options in Cali.
KAHR CW,PM,P series. Small single stack carry guns. Decent guns but can have a bit of a hit and miss rep.
HK P2000
HK USPc
Beretta PX4
Those three are all polymer but hammer fired. They are excellent guns, however.
Now I am usually really FAR FAR from “this guy” but in your case I really think you should “Get a Glock”.
. It’s super easy to make it 100% factory parts including the sights and slide release and you get 100% or at least 98% of what you want.
The other guns above, while fantastic, don’t give you the striker system you are looking for and that’s a pretty major factor IMO. Now, I myself, while perfectly fine with a striker prefer DA/SA and can attest to those guns quality but I just don’t think they will give you what YOU want.
My 2 cents.