I’m no expert on manufacturing certification, although my son probably knows since he’s in the field, however rationally thinking the objective of certification is to certify the ability to produce product that meets content/purity/safety requirements.
This certification must include manufacturing equipment, documentation/processes, and execution, the specified quantity and form factor of the product dose, as well as the purity of materials and absence of contamination.
So certification is of everything involved in manufacturing the product. Period!