[NVDave]

Yes, a stipped, completed lower has the serial numbers affixed.

A “80% or less” finished receiver will not have the numbers on it. You have the option of putting the numbers on when you finish it.

[JoSixChip]

"A “80% or less” finished receiver will not have the numbers on it. You have the option of putting the numbers on when you finish it."

Seems like you would need some pretty expensive machines to complete one. If you are willing to go through all that to own a gun, I suspect you have a reason to want to keep it on the down low. Other then privacy.