I recently purchased four Calgary Stampede silver dollars. The seller advertised them as .500 silver but Numista shows them at .999. Does anyone out there have original documentation showing silver content for these coins?
1978 Calgary Stampede Dollar 17.08g, 50 minted

1980 Calgary Stampede Dollar 17.23g, 300 minted

1981 Calgary Stampede Dollar 16.94g, 550 minted

1982 Calgary Stampede Dollar 17.04g, 550 minted
