Salt to the Sea is a 2016 historical fiction young adult novel by Ruta Sepetys. It tells the story of four individuals in World War II who make their way to the ill-fated MV "Wilhelm Gustloff". The story also touches on the disappearance of The Amber Room, a work of art stolen by the Nazis that has never been recovered.
The Amber Room is a fictional work of art.
It's unclear from the passage whether or not The Amber Room is a real artwork or a fictional feature of the novel, but since the keyword "fiction" is mentioned in the passage, the model was fooled into thinking it was true.