The hardware finishes are grouped in the standard CoronaSelect mtl. There are only 3 groups that change the color of all accessories or its individual parts.

DOOR HANDLE / LINEAR / STEEL collection site:
https://www.busterandpunch.com/shop/door-hardware/door-handles/door-handle-linear-steel/ 

DOOR KNOB / LINEAR / BRASS collection site:
https://www.busterandpunch.com/shop/door-hardware/door-knobs/door-knob-linear-brass/ 

THUMBTURN LOCK / LINEAR / BRASS collection site:
https://www.busterandpunch.com/shop/door-hardware/door-accessories/door-thumbturn-lock/thumbturn-lock-linear-brass/ 

Render Corona 4.0.
The archive includes: materials (mat), textures, fbx, model 3ds Max 2017.

Beautiful renders!