My guess is it will be a purchase order from one or both of the...

My guess is it will be a purchase order from one or both of the acquired IDTFs.
The TMT analysis in https://www.tmt-analytics.com.au/uploads/7/7/9/5/77956374/g_medical_flash_note_30_november_2018.pdf says

“With the Chinese manufacturing facility ramping up for volume production in the next several months, we anticipate GMV will initially want to fulfil orders it may receive in light of the beneficial reimbursement environments through its IDTF’s in the US.”

A previous Company update also gave the hint that the IDTFs have been providing services from monitors supplied by others, and they would rather flog the Prizma as it’s their own ‘hardware’.
I don’t think they necessarily need the OTC approval just yet, as it’s better to be prescribed by the cardiologist / physician and distributed by the IDTFs with additional services provided to the physician. This provides more credibility as a medical grade device useful to the medical fraternity, not just a consumer gadget that doesn’t need some review of results by a physician or nurse via the IDTF services.