The better question is - do they actually care enough and does it matter OOC or IC to them - and the answer is no.
Much like the clearly labeled "lies" that were spread by Soliferum about Nighthelm, or the ones Nighthelm spread about Soliferum, your view of your opponent doesn't have to represent or care about them.
All Vallyn needs to know about Aurvandilian culture (and he would use that term) is they are Royalists. Anything else is secondary to that one, vile fact. He doesn't care about anything other than that simple truth, and it is a truth. Therefore the rest of Aurvandil's internal RP's are irrelevant to him (and likely anyone else who doesn't really care what you RP inside your Realm.)
Much like I don't really care about the extensive and elaborate RP's for the Bloodstar Faith. Is it impressive - heck yes, but unless one of my characters decides to manipulate them using information like that, its not details I need (or really IC should know).
