Another difference of the sisters?

I am building a Titanic from the Mantua kit, which has many inaccuracies, but is a good starting point. Anyways, my question concerns the railings on the 'lounge roof'- the deck where the compass was located. In a photo of Olympic, the rails follow the lines of the bay windows, and there is 1 sirocco vent on the port side. I have seen photos of Peter Davies-Garner's wonderful model, and the rails go straight across both bays, with decking between, and sirocco vents both port and starboard. The Minicraft model has both sirocco vents, but the railings follow the lines of the bays, with no decking between.
Is there any way to know what is more accurate? Were the 2 ships different here?