I am waiting on the form 4 from my dealer to register my Primary Weapon Systems Diablo 7" barrel 7.62 x 39 rifle. Next year when the approval comes back, I am considering a AAC 7.62 x 35 9" Blackout. Supposedly, I will be able to use one of AAC's suppressors to suppress it. I know that I will have to register the suppressor, but do I have the register the blackout upper since my PWS lower will already be registered?