This is a fascinating question both because the intuition might be that there is no need to specifically 'mark' sound, and on the other hand there's the question of exactly what can the body use as a timestamp. What mechanism can mark a signal to have occurred before another, if the signals arrive somewhere out of order?

I’d love to understand how these different neural areas work, exactly — is it a matter of the rest of the machinery effectively writing and reading these areas in a fixed order (and then looping back because it's not an infinite buffer, only long enough), or if there's a different sort of mechanism at play, like each of those different areas introducing a delay of its own. Sounds more like the former?