My experience with vintage lighting, which we collect, (Art Deco, Art Nouveau, Egyptian Revival and Machine Age) is that it almost always is made of non magnetic materials, as the older ceilings were in many cases lathe and plaster and could not support substantial weight. Spelter, or white metal with an applied finish or cold painted would have been much more common....
The types of brass ring connectors at the top of the "vines" are typical of modern production, as is the style in which the leaves appear attached to the "vines"
I am thinking that it is actually modern production Chinese, as the amount of current production lighting produced there is mind boggling.... At least in the images the glass appears to have a texture to it, and appears to have been pressed into shape.... Something I do not see an Italian manufacturer doing a lot of.....
Craig