I brought all the copies of the tickets for all my trips in and out of Canada to my test/interview just in case the citizenship officer asks for it because I was missing one stamp when I crossed south of the border.
My suggestion is just to keep them handy but don't take them out of the envelope unless the officer asks for it. The officer only made a comment on one of my trips to the US because I only stayed there for less than 24 hours. I told her that we crossed the border to go to the outlet mall for that day and she was fine after. I was then told that I should receive my oath invite in 2-4 months.