In Devarim Rabbah 2:24, there is a story where the Rabbis pay condolences to a Roman senator who committed suicide to save the Jews. The Rabbis hint that it was a shame that the senator died uncircumcised, whereby his widow shows them his foreskin.
The plain sense of the passage is that it was a shame he died uncircumcised because he died a gentile. But then wouldn't he have needed a beit din to become Jewish anyways?
One could posit that a local beit din did it, but that seems a bit force; I was wondering if anyone has explicitly addressed this question, or if I'm misunderstanding the laws of gerut.