Specular isn’t in use. It comes in through roughness and was set already. Although, I found If I went and changed a constant it would change how it looks to something that is more realistic. Now it looks more like brick with muck on the walls than painted brick with muck on the walls. 
Here’s a side-by-side comparison.
Here’s what I changed from the original Material. Changed the original Add constant from .5 to 1.5 and it looks better… I think.
