Does Prophet Muhammad have knowledge of the unseen?

Answer
Allah is the only One Who possesses absolute knowledge of the unseen
It is established in the noble Shari'ah [Islamic law] that it is Allah the Almighty Who has knowledge of the unseen and no one beside Him..

Allah Most High says:
Say [Oh Muhammad]: None in the heavens or earth, except Allah, knows what is hidden, nor can they perceive when they shall be raised up (for judgment). [An-Naml: 65)

It is also mentioned in the Qur'an that Allah reveals whatever He wishes from the unseen to the Messengers and servants of His choice.

He Almighty says:
He (alone) knows the unseen, nor does He make anyone acquainted with His secrets. "Except a Messenger whom He has chosen and then He makes band of watchers march before him and behind him. That He may know that they have (truly) brought and delivered the Message of their Lord and He encompasses all that is with them, and takes account of every single thing". [Al-Jin: 26-28)

There is no contradiction between the two verses. The first asserts that it is Allah Who possesses absolute knowledge of the unseen while the second conveys that Allah reveals whatever He wishes of matters of the unseen to whomever He wishes.

Did Allah acquaint the Prophet with the unseen?
Muslims have unanimously agreed that being acquainted with the unseen is among the miracles of the Prophet (peace blessings be upon him and his family) and it is obligatory to believe in all what he has conveyed from His Lord the Most High. All the matters of life in the grave after death [barzakh] and the Hereafter were transmitted to us by the Prophet (peace and blessings be upon him and his family) and, therefore, we must believe in them.

Based on this, there is no harm if Allah Almighty acquaints some of His servants with certain matters of the unseen. The Prophet (peace and blessings be upon him and his family) tops the list of such persons. A group of scholars stated that the Prophet did not die until Allah Almighty disclosed to him knowledge of all creation, in this world and the Hereafter; the Prophet (peace and blessings be upon him and his family) said: "Everything was disclosed to me and I knew." This is the preponderant opinion of Muslim and Azhari scholars such as the Sheikh of Islam, Ibrahim al-Bajouri, and others. Accusing those who maintain that Allah acquainted the Prophet with matters of the unseen with kufr [disbelief] is the act of the Kharijites who attribute the verses of shirk [polytheism] to Muslims. Shirk means to believe that a person is able to know the unseen by himself without attributing it to Allah the Almighty.