Hi Paul,
I cant give you all the answers I am afraid but I can tell you with 100% certainty that not all Waterford is marked. I dont know the full details if its just seconds not maked, some seconds not maked, all seconds not marked. They may even do some first quality stuff and not mark.
I have a few pieces that I would assume to be second quality that have not been maked, wine glasses where the foot is quite obviously not round and a couple with marks inside the glass.
michelle