ak74U_black_col skins keeps getting erased by plutonium launcher
It seems like the ak74u base textures can't be modded using the images folder.. each time you launch plutonium the launcher downloads the original file and replaces the camos you can download here. easy way to go around this is to drop the camo after the launchers updates. it occurred using the asiimov ak47u skin.
Try to create a iwd file for your custom skin, with a bit of luck the iwd file has a higher priority than loose files.