Im stuck with a dilemma now, as i like the gold trim but that would mean 2nd company, which already has the last captain named with rules, which would negate my idea of having the same company lead my planned Astral Claws and future Red Corsairs army.
I don't know if there are any details of how the corruption spread through the chapter anywhere, but maby your (invinted captain) was corrupted earlier than the second company's captain. Then, as part of the chaos gods' plan for turning the whole chapter your captain either 1) covertly took command of some of the second company or 2) re-painted some of the marines under his command to look like the second company thus focring the Second company captain to take responsibillity for his actions and thus leading him down the path of corruption? Then your collection and the games you fight are those actions
Bit of a crowbar move, but it's not as if dressing your soldiers differently or just messing around with uniforms hasn't actually happened. Look at what's supposedly happening in Ukrane right now!