I have seen many answers and comments (here for example) which seem to indicate that the Biblical Unitarian position is that Jesus was born again or born from above at his resurrection. The idea is that believers also experience the born again experience at their resurrection and not during this life. "If you are still flesh, you are not born again - or 'from above' as Jesus put it." is the most direct quote I could find.
Additionally I have seen it said that Jesus is not "in" the spirit...he "is" spirit. In other words, coupling the assertion that if you are still flesh you are not born again with the assertion that Jesus was not born again until his resurrection seems to bring the conclusion that Jesus did not rise in flesh.
From an answer to an unrelated question:
The earlier Unitarians accepted the notion of a physical resurrection, but most of the story is now interpreted in a symbolic fashion. - The Encyclopedia of World Faiths, p136, Eds. Bishop & Darton, MacDonald Orbis, 1987
The question is, Do Biblical Unitarians not believe that Jesus' physical body was resurrected from the grave and ascended into heaven ... that he is only spirit and not flesh?