If you still have yours available could you let me know what markings it had on it?
I bought my Allegro hall effect sensors about a year ago from an E-bay seller. I bought both 5 each of their analog sensor and switch sensor. Part number and device markings are:
Allegro analog hall sensor part # A1323LUA-T Device marking = 23L
Allegro digital switch sensor part # A3213EWA Device marking = 13E
Lefty