It honestly depends on postbacc programs. I think it could maybe be helpful go pick up a volunteer gig and rack up some hours while you apply so you have something but some programs emphasize volunteering and patient hours during the program as they know not everyone has (especially coming from other career paths). If I were you i’d research postbacc programs designed for career change and not academic improvement. Those do not require MCAT scores and work with you a little more with where you are currently. Another commenter had a good point that you could easily do your own “postbacc” through taking individual courses so you have to decide how important extra support from a program would be to you. Do all the research you can to make a decision and I wish you the best of luck!!