Yes. Some souls are already enlightened before incarnation.
When the avatars of Vishnu like (7) Rama, (8) Krishna, and (9) Gautama Buddha take a body, as emanations of the Divine they teach us how to be enlightened. Rama and Krishna were known as Divine as children. Gautama acted a teaching role by acting as if he were an ordinary prince, who took up meditating out of misery or sympathy with humans in misery. There are other amsha (partial) avatars, who come to aid humanity between the times of the great avatars, such as Uddhava, who promised to incarnate often in the Dark Age until Kalki, the 10th Avatara, will come.
When sadgurus take a body, they are already enlightened beings who come to teach and bless humanity. There are others who are enlightened avadhuts (beings from other realms,) who come to bring spiritual light to all nature and sentient beings. They choose to live anonymous lives either among us or in seclusion. Sadgurus Rama Krishna and Ramana Maharshi were born enlightened, but in this Dark Age, they needed to show humans how to become enlightened in the same way Gautama did, pretending to be regular humans and later showing their great spiritual power and teaching. I have had the privilege of spending time with four sadgurus, and no matter what personality mask they wear, there is no personal ego there at all, only a desire to serve the Divine Mission.
There are other highly developed souls who incarnate still seeking enlightenment. While all souls are already enlightened, our mind-ego is not. We seek to remember who we really are and keep at it until finally we annihilate our own egos through vairagya (detachment from our emotions, and finally from our own ego.)
Souls incarnate at various levels of development of the ego-mind-personality. Our world is a very dynamic place. Some souls are coming for the first time from the lower lokaas, and they need to learn how to navigate life in the lowest lokaa of light instead of the over materialism of the lower lokaas.
Most of us are somewhere in the middle between being newbies and getting to the higher levels of samadhi. We come back again and again trying to develop ourselves spiritually. Some of us are very entranced by what glitters and what we can possess, taking longer to wake up and try for enlightenment.
Others are quick learners. Some of those quick learners are souls which have come from other astral planets specifically to rise from stasis to enlightenment via the chakras, which are only found in humans.
When souls have reached enlightenment, they have a choice of merging with God, pouring the teacup back into the Ocean of Bliss, or pledging to keep coming back to aid other souls in reaching enlightenment. This is the Dasa vow in Sanatana Dharma and the Bodhisattva vow in Buddhism. Either choice is fine, and we will choose according to our nature.