The KAC PDW is not a California legal gun, and the way it's built, I don't believe you could make it legal.
Also, KAC does sell their weapons to the public, but I cannot say whether or not the KAC is available in Semi-Auto only. If they do make it semi-auto, then I see no reason why they eventually won't sell it to the public. Being KAC, I'm sure they'd sell it for $3-4k minimum. What else would you expect from a company that sells the Mk11 Mod0 for $10k when it's only worth $3k?