Better post this to make the DOJ's position clear:
If I remove the characteristic(s) that make my firearm an assault weapon, do I still have to register it?
NO, BUT THIS APPLIES ONLY TO FIREARMS DEFINED AS ASSAULT WEAPONS BY CHARACTERISTICS (Penal Code section 12276.1, SB 23). THIS DOES NOT APPLY TO ORIGINAL ROBERTI-ROOS ASSAULT WEAPONS OR AK and AR-15 SERIES WEAPONS.
The removed characteristic(s) must never be replaced on the weapon, or it will again become an assault weapon and would be illegal unless registered on or before December 31, 2000. If you think you will ever replace any of the characteristics that make it an assault weapon, you should consider registering the weapon on or before December 31, 2000. If you do not register the weapon, and decide to replace the characteristic(s) that make your firearm an assault weapon, you will be in possession of an illegal weapon.
Again, removal of assault weapon characteristics only exempts non-Roberti-Roos and non-series assault weapons from the registration requirement. Roberti-Roos and series weapons must be registered regardless of characteristics.