Not sure if I understand your entire question, but here goes...
If you own a M1A w/ a flash hider before the 2000 ban in CA, you would have had to register it as an Assault Weapon. If you didn't, you would either have to give it up to the police, sell it out of state, or keep it but have the flash hider removed...replace it w/ a muzzle brake)
Now, if you still have the M1A...now w/ the muzzle brake on there to keep it legal in CA, you can sell it to another person in CA. You can also sell it out of state and ship the Flash Hider w/ it so that person can put the flash hider back on (w/o bayonet lug...unless your M1A is a "preban" M1A"...different than pre 2000 Kali AW ban)
As for what it is worth, it really depends on what kind of M1A is it, standard, NM, SM, etc. etc. Need more info.