I'm aware you can amend the form 1 to add calibers so you can swap uppers, I was just curious if any other changes, like those mentioned, would also require some form of gubmint permission first.
I haven't decided for sure yet, but thinking since I just ordered a suppressor for it (form 3 was approved so it's on its way from the place I ordered it to my FFL/SOT in my state), won't do form 4/prints, etc until it arrives....but I figure if I am going to "be on uncle sam's register" for that, might as well go all the way, form 1 it as an SBR and not worry about the whole dang pistol brace BS, especially if I'm free to ad, remove, change accessories at will.
I have no plans to move from this state (or this house) ever, so not concerned about the crossing state lines stuff either.