I fixed the totally black grass in harley a while ago MGM lion, I think it's lit by specular, at a guess. But supporting flat shading is the first step to fixing that bug
Looking at the statue, I guess they wanted her to have an aspect of bright gold, specular can be a good catch. BTW, you have managed to unravel the mysteries of specular shading, it is very difficult to make it work?
The maths to do it isn't too hard. Bart already had a pretty reasonable implementation in his shaders. I just don't know the correct bit to turn it on.