Here are the image maps for the outside of the generator (shown 50% size)

The RGB Map:

The Bump Map:

and the Reflection AND Specular map:

One of the interesting things for this render, is I probably don't need a Specular map, as I will be using an HDRI image to light it and with HDRI's and environment maps in general, the highlights show up more as reflections, not specular. Not to say specular is ignored, only that it's less visible in HDRI renderings. This is an old trick which has been used for awhile now in car renderings like: