Assuming that the no-hair theorem https://en.wikipedia.org/wiki/No-hair_theorem https://en.wikipedia.org/wiki/No-hair_theorem applies, once the black hole is

Assuming that the no-hair theorem https://en.wikipedia.org/wiki/No-hair_theorem https://en.wikipedia.org/wiki/No-hair_theorem applies, once the black hole is formed, you can't tell which kind of matter was involved in its creation.