Do you say "the fourth of July" or "July the fourth"? Similarly in Hebrew there are multiple date forms even once one decided to ignore years (and variant spellings for the months). WRR use three forms:

aleph Tishrei, aleph b’Tishrei, and b’aleph Tishrei.

The last form is unusual, akin to saying "on the fourth of July". And, once we allow that, what about b’aleph b’Tishrei? There are also aleph l’Tishrei and aleph shel Tishri with a possible leading b’.

Experiment of Bar-Hillel, Bar-Natan and Mackay