SBR's are not illegal for everyone in CA, just most of us. Complying with the NFA is your responsibility, not their's. I don't understand your issue with threaded barrels. The only law that has a problem with them is with detachable mag pistols. No problem on fixed mag pistols (which when I bought a marketed as "SBR" upper I used mine for) or if you have a CA issued permit to get an SBR.
You have to comply with the NFA but an upper is not a controlled part, nor is it a firearm in and of itself.
If that is the text of your e-mail at the bottom of your post, I don't see anything at all suspicious. That upper you mentioned WITH a threaded barrel is good to go for anyone in CA without any NFA or CA permits to do a nice pistol build. I also don't see any mention of an SBR in that e-mail.
Last edited by stix213; 05-03-2013 at 12:18 PM..