From extensive research(yeah, research..) playing counsterstrike source, It appears the specular map is projected from the centre of the camera position, using a 3dsquare projection that is not dependent on the view.
Which suggests a cube map that is not being tex-gened from the entity's model viewmatrix, but is actually using the cameras positional matrix(Not rotation, otherwise it would warp when the camera turned), probably feed into a vertex/pixel shader. (You can pass 4x4 matrix pars, so doesn't matter if it's a built in feature, it's still possible.)
Which suggests a cube map that is not being tex-gened from the entity's model viewmatrix, but is actually using the cameras positional matrix(Not rotation, otherwise it would warp when the camera turned), probably feed into a vertex/pixel shader. (You can pass 4x4 matrix pars, so doesn't matter if it's a built in feature, it's still possible.)