On my copy, there is a small rectangular sticker in the lower left corner on the back of the jacket with a barcode and the number A2567. Since this number is not actually printed on the jacket itself, it is impossible to say for certain if this might be the reference number. Nothing else resembling a reference number appears anywhere on the jacket or disc labels.
Unlike the Hong Kong release [ML 603], the width of the letterboxing varies slightly throughout this disc. At times it is as wide as 1.78:1, but most of the time it is 1.66:1.