Currently CSAT does not have any plate carriers in their faction-camo available. Using NATO carriers (have US flag) or AAF carriers (green digital camo does not match) is a less than ideal solution.
For comparison, the values of plate carriers vs. the default CSAT harness, based on recent dev built:
(armor, mass, passthrough)
Rig: 5*1/ 80/ 0.4
RIG GL: 5*1 /80 /0.2
Default OPFOR harness: 5*0.4/40/0.8
Due to the noticeable difference plate carriers make in terms of damage resistance when compared to CSAT's default harnesses the addition of CSAT specific plate carriers would give more options to mission makers in terms of CSAT's survivability.