Until a barrel is attached to a rifle, it's just a piece of pipe.
Nope, it's a gun barrel, and as long as you have the parts and ability to make something illegal, they can argue that is the same as having the restricted item. If it were unchambered, or not threaded to fit in a receiver yet, then yeah, it's a tube. Once it's ready to be screwed on, you've crossed the Rubicon.
If you don't have anything to put it on, then you're fine and it may as well be a pipe.