Submitted by Steve
No way of knowing—but the Vedas are centuries later. I do not find much attraction in theories that conjure up Brahmanical deities, even later Puranic deities, in connection with Harappan images. We require a modicum of “chronological discipline”(—let us choose a better term for this in our discussions).
As the Indus civilisation is pre-Vedic it would be more correct to talk about the survival of Harappan religious elements in the Rig Veda. I do believe that there are such survivals. You will find some discussion on such survivals in the papers by Asko Parpola and myself . But you must remember that these are still speculative and await final proof which would come only with the decipherment of the Indus script.