Right. You cannot sell an 80% lower you finish regardless of any intentions. You have to at least finish the lower before 10/1. I'm not sure about the complete rifle build part, but mine will be complete prior to 10/1.
Incorrect. You are free to sell an 80% lower that you have finished as long as it was not built with the intention to sell. You must engrave the lower with some type of serial number if you do sell it so it can be identified.