The three ships initially released on the 12 backs were re-released on 21 back cards along with the Darth Vader TIE Fighter. The 21 back featured the same 21 photos as the equivalent Kenner action figure cardback, but also featured photos of the available die cast range. The photos included images of prototypes for the large sized Series 2 ships, the TIE Fighter was renamed ‘Imperial TIE Fighter’ and Kenner QC failed to spot the typo in Millennium Falcon. The ‘kid-sized’ blasters were still featured but the light saber was removed.
More details on the prototype Series 2 ships can be found on the SWCA
http://theswca.com/index.php?action=disp_item&item_id=53037