No, you won't be fine. Customs doesn't read everything the RCMP labs puts out. They have a blanket procedure when dealing with incoming airsoft: seize and destroy. They don't care what fps it's running at. Parts and internals are a different matter for the most part. But anything gun looking, you're SOL.
"Anyone with a name like Amanishourbariki should give a few letters to the poor Ng family." - Snarfangel, Fark.com