The authors refer to the CG8713 gene product as Sandman, which is a single molecule. Flybase associates this gene with a single polypeptide, predicted to be 395 amino acids long [1].
My research skills are rusty, but I found a paper which makes it sound like this channel is probably a heteromer [2].
So yeah, the ion channel is almost certainly composed of more than one subunit (and thus more than one polypeptide, and more than one molecule), but the researchers are focusing on this subunit.
