All undergrad coursework done after the completion of your bachelor's degree is considered post-bacc regardless of when, where, and what courses you took. On AMCAS, you are to put in ALL college coursework, and this includes any college coursework done ages ago. By definition, post-bacc GPA is included in the overall undergraduate GPA, however med schools can differentiate between your undergrad GPA (from your BA/BS program), and post-bacc.
Since you are typing in all this stuff into AMCAS, it doesn't really matter when or where you took these courses. Your transcripts, sent from all colleges that you attended are there for confirmation.
Should be true for all CA public schools, and I wouldn't be surprised at private schools as well. UC's offer open campus through UC Extension. As far as I am aware, SDSU also has an open campus program. SJSU, and SFSU (not the UCSF one) have their own post-bacc programs, which appears to be no more than a open campus type thing too (not really structured). Your program seems very beneficial, since through UC Extension, you are dead last to register (after freshman)..lol.
Luckily since you should be taking upper division classes, not many freshman/sophomores are competing to get into those classes compared to junior and seniors. So might not work out too well. Personally I got in all the classes. I had to wait maybe 1-2 weeks before I got in sometimes, but it worked out in the end.