This is a list of glass houses that used Harrach blanks. It is from the Harrach project page. What Mike say makes sense. It was difficult to see the depth of the engraving initially, but after the discussion I went back and copied them and enlarged them and they do not appear that deep. This would lead me in the direction of Mike's suggestion, that it is a Harrach blank decorated by a contemporary....
This list, per the Harrach Project page, is only a partial list.
Moser, Fritz Heckert, J & L Lobmeyr, Josephinehutte, Egermann, Goldberg, Muhlhaus.....
Craig