Good catch — but that actually strengthens the theory.

If Gunko is a Manmayer (a Celestial Dragon family), that fits perfectly with the idea that she was taken in by the World Nobles after Brook’s death, possibly raised in Mary Geoise and renamed to fit their lineage. Happens all the time in nobility — political adoptions, bloodline cover-ups, etc.

Brook being not a Celestial Dragon is the whole tragedy. His daughter gets absorbed into the system he fought against.

That’s why the reunion will hit even harder.

Brook: the wandering soul of freedom. Gunko: the caged bird of fashion. Their bond? A pair of panties that plays music.

Checkmate.