Just once Padre Pio celebrated a "Missa Normativa," or interim Mass, and never did so again, begging to be dispensed. He never said Mass in Italian or facing the people. Pope Paul VI's Novus Ordo Missae of 1969 was introduced more than a year after Padre Pio had died.
"Even before the end of the Council, in February 1965, someone announced to him that soon he would have to celebrate the Mass according to a new rite, ad experimentum, in the vernacular, which had been devised by a conciliar liturgical commission in order to respond to the aspirations of modern man. Immediately, even before seeing the text, he wrote to Paul VI to ask him to be dispensed from the liturgical experiment, and to be able to continue to celebrate the Mass of St. Pius V. When Cardinal Bacci came to see him in order to bring the authorization, Padre Pio let a complaint escape in the presence of the Pope's messenger: "For pity sake, end the Council quickly." (Rev. Fr. Jean, O.F.M., Cap., "Padre Pio," apud Angelus, May 1999, p. 31)
Padre Pio was totally obedient to the Church and the magisterium - during the pontificate of Pius XI (1922-1939) Padre Pio was segregated from the Church; he was forbidden to say public Mass, hear confession or answer personal letters. And he obeyed. Only in 1933 was Padre Pio allowed to return to the ministry.
The older priests were not required to learn the New Mass as it would have been almost impossible. I am at work and in between earning my salary I'll try to find you the documentation on that if you wish... but it only makes sense anyway.