Q: I would like to know what readings were read in the liturgy of the Eucharist on March 29, 1969 and on April 20 of the same year. Could you please help me to find the answer to my question?
A: I’m guessing that they were the ones still assigned to the 1962 missal.
Pope Paul VI signed off on the new liturgical calendar on February 14, 1969, and had it take effect on January 1, 1970. So, the previous missal was in force in the March and April of 1969. Alternative readings were available ad experimentum, but not on the days you mention.The Vatican had pretty much finalized the contents of the new lectionary, but it would not appear until June 1969 in Latin.
Easter fell on April 6 in 1969. March 29 was Saturday after the First Sunday of Passiontide, and the 1962 missal had these readings: Jeremiah 18:18-23, Ps 34:20 and 22 (Gradual), and John 12:10-36.
April 20 was the Second Sunday after Easter. The 1962 missal had these readings: 1 Peter 2:21-25, Luke 24:35 and John 10:14 (alleluia), and John 10:11-16. That used to be Good Shepherd Sunday.