I can just give you an european view:
It depends, if the parts of the kit are "adulterated" according to their primary intended use.
If the products are used as intended in the original product, no further labeling is needed, the original labeling must not be removed or changed.
If the intended use of at least one part of the kit differs from the original one, the whole kit is a new product and the repacker becomes a manufacturer.
The concept of "finished device" does not imply that a device when
reaching the final user is already in a state ready for use. Prior to use
further preparatory processing, preparation, configuration,
installation, assembling, adaptation or fitting to the needs of the user
or patient may be required. Examples :
- sterilisation of medical devices supplied non-sterile
- assembling of systems
- configuration of electronic equipment
- preparation of a dental filling
- fitting of contact lenses
- adaptation of prosthesis to the needs of the patient.
The aforementioned activities are normally not manufacturers
activities if they are carried out by the final user as part of the use or
preparation for use. In this context a distinction needs to be made
between a typical professional activity performed by a healthcare
professional and processing and assembling activities done by a
specialist for such processing. In the latter case relevant activities may
become proper manufacturing or assembling activities relevant within
the meaning of articles 11 and 12 MDD.
~ghw