I would say the head looks quite clean, has been decoked at some point, probably 3 months ago by the sound of it. I bet the cams fooked by now though!
But unless you go there and check it, you will never know if it warped or anything? he says he has had it skimmed which means you will be running higher compression (more chance of detonation!)
He sounds genuine enough, but I dont trust anyone on ebay!
Its your call mate.