Maester Steven, may I please ask if you think the Seven Kingdoms at present possess a centralised College of Arms or whether you believe that each of the former Realms maintains its own “King of Arms” and his court? (Also, may I please ask how you would organise a Westorosi College of Arms if you were asked to?).

I don’t know the precise organizational nature, but there are heralds in Westeros doing their job of knowing who everyone is and announcing them at formal events, acting as messengers, etc. And we know that heraldry is taught pretty widely – see the reaction of people to Brienne carrying the black bat of House Llothston. 

However, I don’t know if heralds do the same job of maintaining genealogies and the like – that seems to have been taken over by the maesters, who probably are the ones in charge of teaching heraldry to the highborn.