You do know that post-bacc is merely any upper division undergrad classes taken after earning your bachelor's right? Which means you can just take classes through an extension, do another bachelor's, or ask the school to be course-work only (non-degree earning). One is not limited to an official post-bacc program.
Having said that some of the schools in CA have GPA requirements of 2.7, however most are for disadvantaged backgrounds, with some amount of emphasis for URMs. Those without such criteria are either really competative to get into in some form or another, or merely a course-work only program. Additionally, most post-bacc programs are pretty expensive too.
There are of course some post-bacc programs that feed you into a med school, but there is a higher GPA requirement for that since you must meet a standard for the med school as well.