This is one coin that came in a mix of other coins. Reported mintage for Hong Kong 1980 cents is supposedly 24 million. I tried to research why this particular coin is uncommon. According to NGC and wikipedia: "Few pieces were released for circulation in 1980, but large numbers have found their way onto the market in subsequent years. About 3,500 are known to exist." 5 cents were also minted but not issued. Larger denomination coins were issued. What gives...? Only thing that I can think of is the high silver price of that era but otherwise nothing stands out.
Not sure what the Hong Kong dollar was worth then, but with the current exchange rate of around 7 per US dollar, I would assume that the one cent coin has been out of circulation for quite a while.