All, or most of the regulations governing gun stuff shipped outside of the USA, is in the hands of the ATF, not in Canadian's hands. As long as you have a PAL, (Possession and Acquisition Licence), which is a card that is issued by the Canadian Government, you can bring into Canada, just about anything. There is a web site for all of the information needed at the ATF. This applies to long guns only. There is also a web site that will tell you what long guns are listed as restricted. As to your question I don't know, the reason is that I think scopes are banned, but mounts, I don't know.