Question #1 - Yes
Question #2 - The law is written by lawyers who probably don't know a barrel from a buttplate so it's another grey area. I would steer clear of any bolt bodies or carrier assembly type parts.
Another note: U.S. sellers must be careful when shipping parts to Canadaor elsewhere because registration with the Office of Defense Trade Control and export licensing from either the Dept of Commerce or the Dept. of State could be required. I've said before that the minimum fine for violation is one million dollars so take it to heart. If you want to learn. Go to the Dept. of Commerce website and check out the cases that have been prosecuted. They aren't joking.