I'm not quite sure when the Canadian Forces officially adopted the use of the American M1 helmet. I found these pictures, both from 1960, showing the M1 in wear.




This picture was labeled: Sept. 1960-Cdn - from a veterans online photo album.

I did a little reading on when the M1 was finally adopted by the Canadian Army...apparently it was September 1960. That would make this photo a very early documentation of its use since it is also dated Sept 1960.