Were non-Vulgate Scriptural readings ever used at the pre-Vatican II Mass?
I believe the answer to this question to be yes.
If we count the lawful liturgical variants of the Tridentine Mass such as the Dominican Rite and the Carmelite Rite and permission given to some Religious Orders, we able to see that the Holy See has given various indults for the ...
After the gospel and before the Nicene Creed at Sunday (and holy day) masses, the Epistle and Gospel readings, which had already been recited (or chanted in high masses) were repeated in the vernacular. (Source: I'm old enough to have been there.) The same practice is followed in the traditional Latin masses that I attend nowadays.