as far as I am now able to find out there two changes to the grill. In 1954, together with the introduction of the AZ model (425 cc) the oval around the chevrons disappeared. The A model (375 cc) stayed in production until 1959, but probably with the new grill too.
In 1964 the new version of the grille was introduced, with the logo sitting above the grill with three horizontal bars. The model was still called AZ, but of course it came in many different variants, with three side windows and also the 602 cc engine (AZAM).

On this basis I would not been able to tell you which models exactly are shown on your pictures.