Hi Michael,
That was her intricate scroll work. It was raised and its color has been discussed on other boards. I believe it was a "dark gold" or bronze sort of color. I can't speak to the details of this feature on the Lusitania, although I'd venture to say it was the same color.
When the Mauretania was painted into white cruise livery in May of 1933 for her return to service in June, this scroll work appeared much darker, but that could just be the contrast against the white of the hull and shadows from its relief.
Unless I am misunderstanding you, the MV image you mentioned in my collection, for which I paid a small fortune (a unique photograph, not a postcard), does not appear in that article. Other than the July 2nd, 1935 photograph of her stopping at the Tyne on her final voyage to Rosyth, the latest image in my article dates to the evening of November 6th while she was completing the measured mile off Gourock near the Cloch lighthouse. While I have shown a small scan of this very rare private photograph which was exposed, developed, written and posted on the morning of her eastbound MV departure in some thread or other, I am not keen on posting a printable scan of it. Among other reasons, it is slated to appear in a book in the future. I hope you understand. It is a remarkably sharp book cover quality image - apart from the high quality of the photograph it both shows and describes the fog which initially hampered her departure, yet does not show the damage sustained and recorded on her very rough westbound MV. To which Figure(s) are you referring?
I also have another card, a low production photocard by W&Co, which shows her entering the Canada drydock and bears a message mentioning the eastbound MV departure and posted within an hour of the event on November 16th.
Best,
Eric