I'm not sure all Eisch was signed - mine has a label and a sig but I've just seen a vase attributed to WMF by an auction house, that I feel pretty sure is Eisch (unless they did a direct copy of a WMF vase). I'm assuming the auction house one wasn't signed therefore and probably only labelled and the label had fallen off. My Eisch has a polished pontil mark, however again, I'm not sure if that is always the norm.
m