I will grant that it is pre-Roman, but whether it is even as old as Sumerians would take an amount of guesswork. Hope the Pakis leave something for future archeologists to dig up along the Indus. I suspect we don't know 1% of what could be known of those times, not even which aeon things belong to.
Last year (?) on FR there was an article about the discovery of ruins of a city under a bay on the eastern side of India, and the estimated age was 9500 years ago. Blam probably remembers it. There were (IIRC) shards, outlines of walls, whole houses and buildings (the lines where walls had been) timbers, and so on.
I'll cast my vote for the 3,000BC date.