IMPORTANT TIP OF THE DAYOn default, the Gooch fancy shader defines front facing surfaces in warm yellow, and back facing ones, in cool blue.
Shading Prometheus with the Gooch shader reveals many polygons on the outer surface of
body_gray_81 mesh as
back facing. Naturally, the AO ray tracer would render them pitch black. Those offending polygons are
the cause of black artifacts in the Prometheus hull AO maps depicted in your renders. There may be yet more similar faulty meshes in the model.
You will have to reverse the winding/normals of those polygons manually in e.g. AccuTrans or your C4D (if it provides such an option) to get rid of the AO artifacts completely.
(He-he, sometimes there are unexpected benefits latent even in seemingly useless sheer trifles... )