I've been trying to do some research on this, but unfortunately I've never been able to completely recover all the Battletech paperbacks that I dumbly got rid of when I was a teenager.
Do any of the Successor Lords wear actual crowns? I suppose I'm thinking more in the lines of the Archon, or the First Prince, since I think it is a more European thing, and the Captain-General isn't technically a monarchy.
Though that does lead me to a second question, can anyone think of a reference to a Duke or other noble titled character wearing something like a circlet?
Even if these are only for formal court occasions, it's been something that has been niggling at me.