Exactly that, yes. Spatial information encoded in acoustic information - audio pictograms, almost. The really interesting question then becomes "is it always l

Exactly that, yes. Spatial information encoded in acoustic information - audio pictograms, almost. The really interesting question then becomes "is it always literal, or do they have abstract imagery too?". If it's the latter, that is, in my admittedly inexpert opinion, a slam dunk for dolphin sentience - abstract symbolism allows art.