The type face used for Irish in the leaving cert was originally printed in what I would call Irish Script. There are some interesting examples of exam papers using three different scripts for three different languages.
In 1968, it appears that all the Irish was written in script, including cover of the volume of exam papers. Many of the papers seem to use a typewrite-style Irish script (e.g. the geography paper).
In 1969 the cover switched to a standard Latin script, though the exams still seem to use the Irish script.
In 1970, the cover is still in Latin, but now the Inter Cert exams switch to Latin. (e.g. the history exam). The leaving cert exams still use the Irish script (e.g. the Irish exam).
Unfortunately, many of the exam papers from 1970 and 1971 are missing. I suspect that for some reason, a full book of examination papers was not issued by the department in these years, so I can't say what happened. However, by 1972, it seems all exams are written in the Latin script. My guess is that this was an ordered phase-out of the Irish script and that 1972 was probably the first year with no Irish script for the leaving cert, as (most) students who took the inter in 1970 would have taken the leaving in 1972 and might never have learned to read the older script.