According to the koran muhammad was unsure of his own salvation. The following quranic quote proves this.
Or do they say, ‘He has forged it’? Say: ‘If I have forged it, you have no power to help me against Allah. He knows very well what you are pressing upon; He suffices as a witness between me and you; He is the All-forgiving, the All-compassionate.’ Say: ‘I am not an innovation among the Messengers, and I know not what shall be done with me or with you. I only follow what is revealed to me; I am only a clear warner.’ S. 46:8-9 Meccan