I was intrigued by your post so I did a little digging and found that the Royal Rifles of Canada did indeed send two battalions as part of the CEF but they were the 12th battalion sent over in 1914 and the 171st Battalion sent over in 1916. My personal opinion and I've been wrong before is that no rifle sent over as part of the CEF would be stamped 8 RR as in 8th battalion Royal Rifles.