Rim Worlds Republic MilitaryRim Worlds Paint SchemeNeither of those threads has much in the way of confirmed, canon, specifics. Has anything else been revealed since that I've missed? I didn't find anything in HB:MPS and I'm not sure anything else has been published recently that would deal with them.
If memory serves, Star Lord describes the Republican Guards camo specs resembling those of the Star League, the same olive drab, but it incorporated some dark red highlights, to distinguish itself. There was also a unit, can’t remember which for the moment, I think it might have been referenced in one of the more recent Whitworth write-ups, about an all black Rim Worlds Republic unit.