That seems like a classic mistake of thinking that since California is pro-choice, its GOP voters are moderate on choice. I don't have data to back up this feeling, but in a low-turnout primary, I'd suspect that CA-GOP voters are probably just as anti-choice as many other states that are more conservative overall.
I can't say this with any certainty, but I'd bet that you're right. There may be some moderate tendencies of California Republican primary voters compared to those of, say, South Carolina, but they are almost certainly more conservative than the average California Republican. They are involved in politics so much that they vote in primaries, and because they are Republicans, they certainly believe in the party's platform.
