Here is a snippet of rules regarding Canada exportation from the U.S. to Canada for SKS parts as per a popular website that sells a lot of gun parts:
1. Canada is not on the restricted list of countries from the U.S.
2. General price rule - As of April 1 2008, we will no longer accept export orders where the value of the parts exceeds $100 or that contain a restricted part, requiring an export license from the U.S. Department of State or an import license from the country of destination. (Note: Canada has a $500 parts limit)
3. Restricted Models List: SKS amongst others (and it's classified in the "assault rifle" category when it isn't an assault rifle by definition)
4. Restricted parts: barrels, barrel blanks, bolt assemblies, cylinders, receivers, frames, bolts, and high capacity magazines.
While the part we're discussing is for an SKS, a stock is not on the restricted list for the SKS, and the part is under $500.00. Export from the U.S. into Canada is legal. So having a Tapco stock shipped to Canada passes the stress test.
If this company doesn't want to ship one to you they are doing it out of fear no other reason.
There are companies in the U.S. that will ship stocks here. They may be a little more pricey but at least you'll get what you're looking for.
If all else fails EEEBAAAYYY is your friend.