uppers without a lower are not regulated. Quit trying to be Junior G-man.
Yea I am not sure exactly what is going on but in the last couple of weeks I have seen people trying to sell unpinned 14.5" complete ARs (not just the upper) without labeling it or having it registered as a SBR. Saw one guy asking about if you can turn a mock suppressor to "actually work". There are stupid people out there asking stupid questions about clearly illegal things. LL is right, they will get caught and have no protection here.
Heck I had a 10.5" pistol upper for sale and a complete lower for a rifle in the same picture before (not attached or in the same post, just the same picture) and I got questioned on it. Bottom line, think twice before posting.