Yes. I'm not sure what you're disagreeing with? The discovery was that it is possible to record tinnitus from someone's ear when we thought it was a neurological phenomenon. So tinnitus does actually produce a physical sound, even in cases that don't have a known physical cause like muscular tinnitus (https://dizziness-and-balance.com/disorders/hearing/tinnitus/ME.html). I'm just theorising what could be causing the physical sound in such cases.

edit: oh, I see, this is in context of the question I was replying to. "Physical sound" doesn't mean "it was perceived by something physical" it means it's actual vibrations in the air. We thought tinnitus was just abnormal brain activity, not a physical sound; turns out that is at least partially wrong.