These replicas of commemorative stamps were produced by the Lombardo Mint located in Sherbrooke Quebec Canada. I believe they were made before I worked there for a year. Mr. Lombardo made all of his silver pieces of .999 silver. I would estimate that there may have been a hundred or two of the silver produced and maybe a couple of thousand bronze. (how many could he sell, set the limit for bronze.)
They specialized in high relief medalions with some highly skilled sculptors and engravers and also local "interns" who were at various stages of skill and talent. They operated as Canadian Artistic Dies before Franklin Mint made it necessary to be named a Mint.
It was the height of my numismatic life because in one year I traveled for Lombardo Mint to coin shows in 7 Provinces of Canada and over twenty states, including ANA, CNA, FUN and a lot of others. Met lots of people, saw many rarities. Had a ball. We did a bang up business in Apollo XI medals, Replicas of the Lunar Plaques left on the moon, Robert F Kennedy medals etc. I still have some of that stuff laying around. Hope this helped.