The Indus Dictionary Project
This is a pictograph of an adult person with the addition of what may be two wings or two quivers on the shoulders. It resembles depictions of Ishtar or Venus from western Asia. The Indus inscriptions indicate that the being is of some importance because it possesses both a domain or realm, and goods. Hence, my conclusion is that Mahadevan's sign number 1339 depicts a god or goddess, which may have been Ishtar.
Harappa: Seal: H-476 a: Sayid Ghulam Mustafa Shah and Asko Parpola, 1991: Corpus of Indus Seals and Inscriptions: Volume 2: Page 281: Collections in Pakistan: Suomalainen Tiedeakatemia.
Indus Script Sign Number 1339: List of Sign Variants: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.