The other post on powder post beetle the article I found said over 120*F internal temperature to kill the worms or deep freeze temperatures for several days. I would try freezing first, less chance of warping the wood.
I'm arguing the other way here. The damage is pretty severe. It's far more than a few little pinholes. There's enough wood eaten away to change the outside shape of the molded corners. Were there any pictures of the worm damage in the pictures? That would be the telling point for me. No pictures of obvious damage no matter the cause would indicate fraudulent intent through omission to me.
To find out if you have a live infestation brush all the wood dust off and wait to see if new dust appears. If it does then the little bugs are still in there feasting. Honestly though if the outside of the base looks like that, the inside is far worse. If you were to cut one of the boards in half it would be just a shell.
Rodney