To revisit your original questions --
I think that your customer is not only a "Specification Developer", but a fully regulatory-responsible manufacturer. They should register and list accordingly (and according to the intended use that they assign to the device).
Assuming that your supplier (the actual maker of the device in bulk form) is located off-shore and you are the importer into the USA - I'm not sure what would be the best (and compliant) way to refer to the goods in their export documents. On one hand these might not be Medical Devices per-se (depending on the circumstances, of which I don't have full knowledge); but on the other hand if such shipment is (for any reason) subject to special customs scrutiny, and the FDA somehow gets involved, I'm sure there will be some explaining to do as to any "missing" medical device reference (and maybe the 510k in particular, as the facts will unfold). Perhaps best consult with a customs broker, well-experienced and knowledgeable with medical devices / medical device components.
I think that your customer is not only a "Specification Developer", but a fully regulatory-responsible manufacturer. They should register and list accordingly (and according to the intended use that they assign to the device).
Assuming that your supplier (the actual maker of the device in bulk form) is located off-shore and you are the importer into the USA - I'm not sure what would be the best (and compliant) way to refer to the goods in their export documents. On one hand these might not be Medical Devices per-se (depending on the circumstances, of which I don't have full knowledge); but on the other hand if such shipment is (for any reason) subject to special customs scrutiny, and the FDA somehow gets involved, I'm sure there will be some explaining to do as to any "missing" medical device reference (and maybe the 510k in particular, as the facts will unfold). Perhaps best consult with a customs broker, well-experienced and knowledgeable with medical devices / medical device components.