According to Osho, yes—such rival claims shadowed Mahavira, Buddha, and Christ: Goshalak openly declared himself the true Tirthankara, others were touted as such, and many Jews denied Jesus as Messiah, demanding miracles. Yet Osho’s crux is discerning authenticity: the real one does not need to proclaim himself; being radiates truth. Loud claims betray inner doubt; time and silent presence reveal the genuine.
Yes; many people claimed or were claimed to be the ‘real one,’ but true masters don’t need to boast—their quiet presence shows itself.