I meant that no contemporary account says that Archimedes used mirrors. The idea that mirrors were used was a later idea—same with lenses—despite Diocles’ commentary on Archimedes’ work. Remember that it was the satirist Lucian of Samosata who wrote of the fleet-burning hundreds of years later, not Archimedes himself.
Ah ... I see that I misunderstood/misread your comment. My bad.