your spec map has some dirt at the top that's easily recognizable as a uniformed brush. might want to random that up some because it's repeating on the spec. i would suggest still trying to do a high poly so you can show them your high poly skills as well plus it'll help your normals and diffuse pop out some more. best of…
you said you have 4 shaders with 4 512'x a piece? so this whole object could be made up of 1024x1024 pixels worth of texture space even if it is broken up into smaller maps. A high poly would be good for multiple reasons, you would get nice bevels on most of the edges that would catch light niceley, it will give you a…