Nope not metal for most, think about it….. they were spending so much money for the shows, and for something so small and less visible onscreen for every star fleet actor, than other stuff, they were made of either resin or plastic, I think resin was the most commonly used especially for the Com-badges, as I have a exact replica of the com badge and it is a plastiky resin. I believe the Com badges were made of the same resin too. Thats the key to Star Trek props..Resin…Resin and More Resin. Even some tricorders and props were mostly painted resin out of molds. But to answer you question yes metal was used for most main actors…sisko..picard..riker
So yes maybe not cheap plastic, but…. some resins used resembled cheap plastic, and they rarely used metal for anything. Watch " First Contact ", when they have close ups of Data in the beginning his rank pips are clearly not metal.