I do know that the seminary at Brooksville, FL does not do the Holy Week Mass of Pius XII, and I believe Fr. Cekada is there, a big promoter of the 1949 letter with no AAS number.
The funny irony is that the Brooksville place promotes a similar theory regarding the status of the AAS number as pertaining to the status of an official docuмent that you have posited, though for different reasons:
Fr. Ricossa ("Liturgical Revolution,"
http://www.traditionalmass.org/articles/article.php?id=37&catname=6) contends:
March 23, 1955: the decree cuм hac nostra aetate, not published in the Acta Apostolica Sedis and not printed in the liturgical books, on the reform of the rubrics of the Missal and Breviary. [emphasis]
Well, it took me just ten minutes to find in the
Acta the General Decree of the Congregation of Sacred Rites
De rubricis ad simpliciorem formam redigendis (
23 March 1955; A. A. S., vol. xlvii., pp. 218 sqq.).
It was not printed in the liturgical books (and in at least this statement Fr. Ricossa is not re-writing history), because the Decree itself forbade the Printing Presses to make any change in the typical editions of the Roman Breviary and Missal until further notice. Every Priest and Religious has their
Ordines to help them conform with the "new" rubrics anyways, just like the generation before them used their old Breviaries and conformed to
Divino afflatu until the new typical editions were promulgated, published and distributed throughout the Catholic world.
Despite Fr. Ricossa's embarassing mistake, his book on the liturgical changes is still the textbook at Brooksville.