As with the mono album, the use of a new generation of master tapes was reflected by a change in vinyl matrix numbers. See Appendix B for further details.
It has proved difficult to establish exactly when the revised sides started appearing, as no-one seems to have noticed at the time. Most Dylan fans would of course only have heard one copy of the album anyway. However, from collected details of quite a number of 1960s copies of the US stereo album, it seems that the start of the change process pretty much coincides with the appearance of the revised inner sleeve design (see later). This would date it at around early 1968.