You are assuming that if you have your Form 1 prior to 10/01 you are GTG. This is unclear.
The Form 1 is basically a $200 permission slip, that if approved, allows you to manufacture a SBR. It takes many moths to get approved. Obviously you will not be able to lawfully posses and SBR prior to October 1, and grandfather it on the bases of lawful possession. The AWB will also grandfather an Assault Weapon for which you have a purchase order for prior to Oct 1st. Maybe, the Form 1 meets the purchase order requirement.
Let me go on record as stating that, assuming you possessed the AR15 prior to Oct 1st, I see not statutory prohibition on turning it into an SBR post Oct 1st. I think most who have spent a considerable amount of time looking at the new legislations would come to the same conclusion. However the MSP may not share this interpretation. There has been a lot of conflicting information be reported back by FFL from recent MSP training sessions.
Like you I just did a last min Form 1. If you have a trust, then file your materials online. I did it last night. Once you figure it out, it is a pretty painless process.
Form 2's are for FFL's to use.