I did it and am starting this fall at PCOM. It is modeled on the first year of the DO program. Anatomy, Histo, Immuno, Biochem, Neuro, Pharm, and Physiology use virtually the same notes as the DO class, the profs just don't go into as much detail in the lectures or the tests. Everything I have heard from the first year DOs who did the post-bacc say they did very well because of the background they had.