The materials are 100% procedural.
For realistic patina looks (Silver & Pewter) you might want to use an image map or vertex colors. Watch the instructions video for details on how blender can create "dirty vertex colors" for you within seconds! ... watch the instructions video
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.