Air mixed with air and water mixed with water cannot be distinguished.
How can light merging with another light be seen separately? How can ashes mixed with ashes be distinguished?
Who knows how a body constituted of five elements take shape? How can one discern what happens to the soul when it leaves the body?
Similarly no one can assess the state of such Sikhs who have become one with the True Guru. That state is astonishing and wonderful. It cannot be known through the knowledge of scriptures nor through contemplation. One cannot even make an estimate or a gu