I am personally very well aware of post-baccs and SMPs, being 2+ years into a GPA repair journey myself. The OP seems confused about this whole thing, and I just wanted to clarify this so he doesn't get himself into the same mess the other guy got in.
Also, SMP stands for Special Master's Program. I'm unaware of any SMP that calls itself a SMP that does not give you a master's degree. Temple, for example, has what we think of as an SMP, but it actually calls itself an "advanced post-baccalaureate certificate program" or something like that. It is NOT an SMP.
I think it's pretty clear that if you are taking graduate-level or med school coursework, it counts as GR. If you're enrolled in some program that has you taking undergraduate classes with undergraduates, it counts as PB. Your hypothetical SMP, assuming students were not taking undergraduate classes, would count as GR.