Comment: All they would need

(See in situ)

All they would need

to do would be to accurately weigh it. And then put it in a bucket of water, and calculate how much water it displaces. That would easily show any discrepancy. If they wanted to increase the weight per given volume, they would have to add something heavier, like Lead, along with the Tungsten, but the volume still would not be just right.

Let the buyer beware!