By magnetic, I mean that it would react strongly to the presence of an external magnetic field. The concept of a spinning black hole creating a magnetic field is unrelated to this question.
My guess is no, because:
the extreme forces compressing the atoms destabilizes and destroys their structure to the point that matter inside a black hole cannot even manifest the emergent properties of combining quarks.
information inside the black hole cannot leave it, so it would be impossible to emit a magnetic field due to the matter inside the black hole, even if the matter magic-physics-ally could stay in the form of the atoms used to create it.