Are these Canadian Mounted Police spurs? (i.e. North West Mounted Police, Royal N.W.M.P. or R.C.M.P.?) Pictures?
If so, they would be the same as (or at least very similar to) British cavalry spurs, and the spurstraps would be the same as well ...
If they are Canadian, I can search some of my references - which might at least yield some period photographs that I could try to scan at sufficiently high resolution to hopefully show some detail ...