Additional Lore Time
Based on the Ladies Day event display in Ul'dah, it shows the first three Paladins as mannequins. They happen to be shown wearing the AF2 armor, blue on white. Based on this, I'd say there is no reason why someone role-playing as a Sultansworn cannot wear whichever color they chose.
Personally, seeing how Captain Jenlyns and Phillis both wear the white on silver, I think we could consider that the current 'official' uniform color. I consider the blue and white to be more of a formal affair. Akin to something Crofte would probably wear to the next Royal Ball.
Based on the Ladies Day event display in Ul'dah, it shows the first three Paladins as mannequins. They happen to be shown wearing the AF2 armor, blue on white. Based on this, I'd say there is no reason why someone role-playing as a Sultansworn cannot wear whichever color they chose.
Personally, seeing how Captain Jenlyns and Phillis both wear the white on silver, I think we could consider that the current 'official' uniform color. I consider the blue and white to be more of a formal affair. Akin to something Crofte would probably wear to the next Royal Ball.