Ireland must have been one of the first countries to use copper-plated coins then, if the changeover was 1988.
Copper-plated coins have been around for quite a while; Germany has had them since 1948/49 (1 Pfennig). The 2 Pf coin was bronze from 1950 until 1968, and then (until 1996/2001) copper-plated steel like the 1 Pf.
Cu-Ni plated nickel is, at least around here, much more recent indeed. Came up with with the first euro coins ...
Christian