Sorry to say but that book is full of mistakes!The forward 1st class staircase had the famous "Honor and Glory Crowning Time" of course, but the aft staircase did not. The clock was roughly in the same position but had a simpler surround of wood molding. I first saw this picture of the aft 1st class staircase on page 153 in the book "Titanic & Her Sisters Olympic & Britannic" by Tom McCluskie, Michael Sharpe, and Leo Marriott. They may have mis-identified the picture a bit as the caption reads "Olympic's first class staircase was identical to Titanic's with the exception of Olympic's clock which was far less ornate."
Ioannis, I do realize that; in fact I pointed out one of the mistakes in my post that you quoted. It is unfortunate because when I purchased that book, I was amazed by the many photos that I had not seen before. This was before the Titanic The Ship Magnificent was published. As I became more knowledgeable about the Titanic and the Olympic class, I did notice quite a few picture caption mistakes such as a couple of pictures of the newly launched Britannic incorrectly identified as the Titanic. From what I know only the Britannic of the three Olympic class ships was launched with the forward A Deck promenade already enclosed. Even worse, a picture of the HMHS Aquatania during WW1 is labeled in the book as the HMHS Britannic!Sorry to say but that book is full of mistakes!