The reason i went digging for old texture file is because for me this does not work.
As far as i can tell v2 textures are in a different format, there is no rcs.dds files at any rate, and the parts remain blank.
It seems this mod was using textures from old version of original rcs, which as at some point been removed.
I've managed to restore it by downgrading to version 1.7 and copying file rcs.dds
GameData/Squad/Parts/Utility/rcsBlockRV-105
to
file into
GameData\MandatoryRCSPartPack\Parts\RCS_RV105Variants