I may be mistaken but the uppers as well as lowers are now prohibited under new “law”. You cannot export or import items that are prohibited devices. Yes it’s true that AR uppers and lowers cannot be imported back into US once they have been exported out. To make a long story short ...you’re hooped brother.
From OIC:
The Amnesty Order has been made to protect affected individuals who (1) were in legal possession of a newly prohibited firearm or prohibited device at the time the Regulations came into force, and, (2) continue to hold a valid licence during the amnesty period, from criminal liability for unlawful possession of a prohibited firearm in order to afford the individuals with time to dispose of the firearms. Disposal can include: having the firearm deactivated by an approved business; delivering the firearm or device to a police officer; legally exporting the firearm; and, if a business, returning the firearm or device to the manufacturer. Other permitted activities during the amnesty period are to transport the firearm for any of the above purposes and to use the newly prohibited firearm, if previously non-restricted, to hunt for the purposes of sustenance or to exercise a right recognized and affirmed by section 35 of the Constitution Act, 1982 (the Constitution). Individuals are no longer allowed to import the firearms listed in the Regulations. Affected owners will no longer be permitted to sell to individuals within Canada or use the prohibited firearms, and no transportation will be permitted except for the purposes described above. The firearms will have to be kept securely stored in accordance with the legal storage requirements for the classification of the specified firearms prior to their prohibition.