Yes, a black color sheath which is given for conventional outdoor fiber optic cables is not recommended. Since this plenum cable would be installed along with other cables, it must be identified separately by its sheath color.
For Non-military applications, OM3 fiber cables have a light blue color. OM3 fiber has a core diameter of 50 microns and a cladding diameter of 125 microns. For Military applications, the sheath color is not specified and hence you can negotiate with the end-user.