After some research I decided to take the plunge and get an SBR ar-15. I will be buying a new lower so do I buy and register the lower as a rifle first or do I start with the paperwork. I will not be going the trust route so do I just send in the form 1 http://www.atf.gov/forms/download/atf-f-5320-1.pdf along with my fingerprints and $200?