I honestly can’t remember. sorry!
It’s been a bit since I was actively playing on Siptah… like a couple month ago. Right now I’m just refreshing until I get back to it. That being said, I KNOW those were from breaking down stuff. I believe it’s from one of the surges. If I recall correctly, there’s some npcs that wear rusted armor. If they drop it, I would break it down and get those.