Leading off the “second instruction” is a chapter entitled, “Options in the Texts for Mass.” Here it is:
1. Outside Lent, on days of class III, the Mass either of the office of the day or of the commemoration made at morning prayer may be celebrated. If the second is chosen, the color of the office of the day may be used, in keeping with the Codex rubricarum no. 323.
2. Once the conference of bishops in its own region has sanctioned an order of readings for weekdays in Masses with a congregation this may also be used for Masses celebrated without a congregation and the readings may be in the vernacular.
This order of readings for weekdays may be used on certain days of class II, to be indicated in the lectionary itself, and in all Masses of class III and IV, whether Masses of the season or of saints, or votive Masses not having their own, strictly proper readings, that is, those that mention the mystery or person being celebrated.
3. On weekdays in Ordinary Time, in the celebration of the Mass of the Sunday preceding, one of the Prayers for Various Needs or an opening prayer from the votive Masses for Various Needs may be taken from the Missal to replace the prayer of the Sunday Mass.
So we see more vernacular creep: now it can be done in weekday Mass readings celebrated without congregations. Everything else pertains to priest prayers and the various choices clergy had in the 1962 Missal.