Hi Katana,
If that has been sharpened then you're right, it was probably 'live'. It seemed ceremonial only in the sense that the features had devolved essentially to less dramatic form. Terms expressed as 'elephant sword' 'gun' etc. are always confusing. I cannot imagine trying to kill an elephant with one of these, although the ribbed four blade shape seems much like 'armor piercing' weapons. I'm not sure on the significance of the winglike shape, and perspective on those features we can only speculate. There would probably be some pretty good suggestions found in "Hindu Arms and Ritual", as Jens has mentioned.
Good observation on the shaft size also, and that might support use for anti-elephant warfare. Maybe this was sort of a proto-bazooka?
In any case, I think your descriptions probably revise the ceremonial suggestion. I'd like to find out more on the use of these weapons associated with elephants, as well as the ancus, which is a most mysterious implement/weapon.
Best regards,
Jim