As I recall, a document that allowed women to be readers clearly said that women were not to do so from within the sanctuary.
That is a good point. Younger folk like me might easily and incorrectly think that all the liturgical changes took place at once. Big changes did happen overnight, so to speak, but there are other things that started here and there, taking more time to run their course.
On this particular point, I know of local provisions, approved by the Holy See, that had such an arrangement (women can proclaim a reading at Mass but only outside the sanctuary). By the time of the 1970 document “Liturgicae Instaurationes”, it was left to Conferences of Bishops to “give specific directions on the place best suited for women to read the word of God in the liturgical assembly” (n. 7 of that document). I do not know of how any conferences handled this possibility.
The 1975 General Instruction of the Roman Missal, similarly, stated: "Laymen, even if they have not received institution as ministers, may perform all the functions below those reserved to deacons. At the discretion of the rector of the church, women may be appointed to ministries that are performed outside the sanctuary.
The conference of bishops may permit qualified women to proclaim the readings before the gospel and to announce the intentions of the general intercessions. The conference may also more precisely designate a suitable place for a woman to proclaim the word of God in the liturgical assembly" (n. 70).
As time went on, this distinction fell to the wayside since, for one thing, canon law changed (1983) and so the prior prohibition on women being in the sanctuary was dropped.
Dan