Probably there are iron parts (along with the gold decorations) as well as bronze parts. But anyway, no, the Italian peninsula wasn’t in a stone age then. The Mycenaean Greeks put colonies in and/or traded with various places in Sicily and Italy, and IMO, they were following the precedent set by the Minoans, whom they supplanted in the Aegean, Cyprus, and trading centers in Anatolia.
I’ve often wondered if there was a Mycenean equivalent to the classical “Magna Graecia” of scattered trading colonies.