Dead things remain dead things even when they are unrecognizable - if I state that oil is partially composed of dead dinosaurs most folks won't find that statement disagreeable.

I think it's pretty fair to describe the remains as dead robots similar to folks talking about their coke-bottle decks (recycled plastic) or even a sword forged from the remains of dead robots - I'd still consider that to be made of dead robots even though very little remains outside of the mineral composition.