Anything earlier than 1982 will be copper. Anything after 1982 will be copper coated zinc. Both types were made in 1982. Personally I like to use the drop test on the 1982s. Drop a coin you know is copper on a hard surface (just a few inches up) the copper will ring when it hits. Repeat the test with a coin that you know has the zinc center it will not ring but have more of a thud when it hits.