(update)
Pistons & sticky pistons have been designed. The iron parts were flagged as metallic and the sticky goo has high smoothness, so if your shader supports these PBR parameters, they should behave as expected !
edit: changed the image to reflect latest changes.
edit2: the pack currently supports roughness-metallic as PBR format, but later down the road I might develop Continuum-compatible extension or more probably LABPBR format to account for more material parameters.
HardTop Vanillaccurate 