They are referring to the gold mat that frames the photo. pictures are framed by a gold mat. A gold border that is separate and then glass to protect it. The image will have to be removed from the mat frame to see the imprint on it. Plain styled mats are usually earlier while patriotic mats or floral designs are during the war. It is extremely common that images get moved from cases. While it may not be the one it originally was put in, the case itself is still worth a good amount on its own. The original case could have broken and the image was moved to another. Both the image and case are real and authentic pieces of the period but possibly have been "married." That company also guarantees every piece so you can also return an item if not described correctly