I have never seen anyone apply a gloss and a spec. map in cycles and I would be very interested to see how this is done so I can start using the gloss textures I have from gametextures.com. Some also have a height map which I assume I am supposed to just use on a displacement modifier.
Here are a couple of examples to illustrate some of the possibilities of nodes using a single texture like this:
Using the texture as color on a glossy shader.
Using the texture as roughness on the glossy shader, the roughness value is determined by the brightness of the image, dark areas are more reflective.
Using the image as Roughness on the glossy shader and as Displacement (bump map) on the material output:
Using the image as a mix factor for two different shaders:
Using an RGB Curves node to alter the contrast of the image used as factor.
Using RGB curves to control the displacement
As you can see, there are quite a number possibilities for endless fun.
I used the 4 images on their pricing page in my demo.
The Albedo Map goes in to the Diffuse node as the base color.
The Specular Map goes in to the Glossy node as the specular color. (metals are one of the few materials that have a colored specular highlight.)
The Gloss Map is used as the mix factor in the Mix Shader node between the diffuse and the glossy.
The Normal Map get plugged in to a Normal Map node then connected to both the diffuse and the glossy nodes.
Gloss maps should be inverted and plugged into the roughness input of glossy shaders.
Specular maps should be plugged into either a mix node factor input or into a glossy shader's color input (if the material is a metal do the later and do the former if it isn't).
Height maps can be plugged into the displacement input of your material output, fed through a bump node or used in a displacement modifier.