It seems that Moi.ini calls the MoiColors....3dm file. (Both files may be located in appdata/roaming.)
I am unaware of another way to edit the .MoiColors....3dm file, other than via the styles menu?
- Brian

I have a few other ...Colors....3dm files, like MedievalColors.3dm file. Turnsole, Woad, Indigo, Smalt...