The WAC insignia was widely used. It would have even been on the buttons on Aunt Marian’s uniform.
The insignia was an image of the Greek Goddess, Pallas Athena. According to the Women’s Army Corps Veterans Association:
… hit upon the idea of a head of Pallas Athene, a Roman and Greek Goddess associated with an impressive variety of womanly virtues…She was the goddess of handicrafts, wise in industries of peace and arts of war, also the goddess of storms and battle, who led through victory to peace and prosperity. Accordingly, the head of Pallas Athene, together with the traditional US, was selected for lapel insignia, cut out for officers and on discs for enlisted women.