I am no glass expert, but my instincts argue against an attribution to barovier e toso. while the lobes are suggestive of their work, they seem too regular and formulaic for bv. the majority of works I have seen by bv have more complicated glass designs, and the applied leaves seem too fussy for their tastes. however, as a long time glass maker, their styles are certain to be many and varied.
fortunately they are a well documented maker, so you should be able to find closely comparable works readily to prove or disprove the hypothesis. even though I would not go so far as claiming bv authorship, I would agree that Italian is a reasonable guess.