The first page of my RCGA Rules of Golf reads:

THE RULES OF GOLF as approved by THE ROYAL CANADIAN GOLF ASSOCIATION, R&A RULES LIMITED, and THE UNITED STATES GOLF ASSOCIATION Effective January 1, 2004

But for the longest time, the R&A governed Canadian golf.

I also believe that the RCGA follows clubmaking rules as set out by the USGA (ie COR limits, etc)