The material is 100% procedural.
However, for realistic looking patina you want to use a map or vertex colors. Watch the instructions video for details on how blender can create "dirty vertex color" for you within seconds!
The .blend file is specifically for version 2.8(+) and the material shaders work both in EEVEE and Cycles.
Note: blendermarket shows Software Version 2.79 because they don't have a 2.8 option yet.