No, the flat is just a sheet of steel. once bent to shape, and the lower rails are welded into place, it becomes a receiver, but YOU made it so it doesn't have to go through an FFL.
as for kits, most kits are AKM pattern rifles, ie russian, romanian, egyptian, bulgarian, etc, and will use the same receiver and barrels.
I can make that work. I will be bringing my pillow and blanky...I get off work at 0600 that morning but ill be there!