Yes, quest it does and the UV edit is quite versatile. This only started out as a workflow example and it turns out you where right about using a 2d app. Metasequioa does import text/shapes in .png (transparency) but with no manipulation.

So this final image had a bump taken from the diffuse - magic wand the 256 black spots -change to white = raised dents)- invert  selection, and paint the rest as mid grey. Back into meta to paint shades of black (indents) A slight amount of reflection is taken from this alpha info.
In conclusion You do need to UV map effectively, as you rightly point out but for me painting on the mesh is so much fun.
Thanks to all for the c+c