You forgot "engrave the lower with your name, city and state" somewhere in there (exactly when to engrave was the topic of a lively debate in here a couple weeks ago).
You must engrave the receiver with the above information when you "make" it via the Form 1. It must be visible and unobscured by anything else on the rifle. This is one of the advantages of buying an SBR -- you don't have to mark it up with that engraving. Of course, from the time you select the SBR you want to when you actually get to possess it could be on the order of a year that way. Going the Form 1 route allows you to possess and even shoot the rifle (with a barrel longer than 16") while you're waiting on the stamp.
O2