Date listing

Why is only the silver proof issue of the coin listed as ND (1982) when the Copper-Nickel version is listed as the 1982 date? The minted coins appear to be identical on both obverse and reverse.

Different understandings of the Numista guidelines. Nothing subtle.

One followed SCWC dating, one followed the last date on the coin.  Both should be the same.  The gold one has 1982.

Guidelines: The year may appear as part of a date range on commemorative coins (1697-1997). If the end year in the date range does not correspond to the year of minting, then “No date” (ND) should be specified instead.

Numismaster has all three as being minted in 1982. That's what should be used.  https://numismaster.com/MC_18772