This is my personal thinking as to why with almost 99.99% certainty that CJ was not SWAT.
Samantha had mentioned in conversation that as they had lost some of their best guys in the ambush, that “one of them was even SWAT”. Now if that were the case then we would know for sure that CJ was also SWAT. Being SWAT members, they would have known each other, or at least the male would have known about CJ. A female making SWAT is pretty rare and wouldn’t go unnoticed. It would have been plain to see for all that they knew each other, unless the SWAT guy promised not to say anything, but that doesn’t make much sense either. She may have the tactical skills found in a SWAT officer but I think CJ had no previous affiliation with anyone else in her tower, and that would include SWAT.