Can someone help me date this OR 120? The removable back seems to be off a different amp. http://i1043.photobucket.com/albums/b434/Oleiber/IMG_0099_zpszfeoc7z5.jpg.html http://i1043.photobucket.com/albums/b434/Oleiber/IMG_0097_zpsbdtf7owi.jpg.html http://i1043.photobucket.com/albums/b434/Oleiber/IMG...