Good catch, Chuggy.
A blind Italian glass collector could spot this as a fake from ten feet away. This seller is a well known peddler of fake Italian glass. Unfortunately, many new collectors have been taken in by him and others of his ilk. One must use especially extreme caution when buying vintage Italian glass from Italy, and for some reason, Austria. The Italians are the most aggressive buyers of good vintage Italian glass. Hence, why would anything good and right be offered from there at a bargain?
Venini started reissuing their patchwork vases a few years ago. Unscrupulous sellers grind down the engraved signature and add a new one. Some fake signatures are better then this. Be on the lookout for obviously stensiled, wide letters and for unusually shaped letters. Best to know who you're buying from and what you are buying.