posted
I was a post-bac student for a year before starting my masters. My university worked this way: If you are planning on seeking a degree or certification with the courses you're taking then you need to be matriculating, if not, do the non-matriculating.
I did the non-mat. for the first semester because it meant that I didn't actually have to apply to their graduate program until the next semester. It didn't make a difference in the courses or the credit.
It DID make a difference in funding- no money if I was non-matriculating, gobs of it once I was.
You might want to check with an adviser to see how your university works.