Third AC got into operation in 1993/93. Phasing out of MG had begun through Project Unigauge in 1992. Therefore, there are no Third AC Coaches. Regarding First AC MG coaches, they were present in the hey days of MG before Project Unigauge. I remember there was first AC in the Madurai-Madras overnight MG train. But there were a few only. Mr PKV with his 1974 TT could possibly tell us the MG trains which had first AC