No I don't think they are legal because it's not a TETRIX part nor a "raw" material.
However, you can buy aluminum channels (without holes) from McMaster Carr or other vendors and they would be legal (something like this:
http://www.mcmaster.com/#standard-al...nnels/=k3x6j7). You can cut them to any length and drill the holes yourself and whatnot. Definitely cheaper and more flexibility but more work.
Good luck!