I don't see anything there to suggest that they exchange pre-decimalisation currency for euros.but from the Central Bank's site below, it looks as if they do.
[broken link removed]
I presume that they mean that Ireland and the other countries listed give this promise?The [Irish Central] bank will continue to accept all Irish notes and coins indefinitely.
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Only in Germany, Spain, Luxembourg, Austria and Belgium do Central Banks promise an indefinite exchange of notes.