stock headers have different bolt patterns, on the 95-97 F model and 00-02 J model... 98-99 G models do have the same bolt pattern altho I think 00 was the first year they had stainless headers. A pipe for a G/J model should be pretty easy to find actually... Pipes for the 05-07 ZZR600 should fit as well.
Of course this all refers to the US models... the 02 ZX6R overseas was actually a 636 engine in a J frame. Not sure what you guys got up there in canada, but I would think it was a US/North American 599cc model.