Recently I found on a bulletpicker website a very interesting document: "CBU Data Sheets", from August 1970. It looks like a compilation of USAF manuals of many different cluster bombs and doispensers.
http://bulletpicker.com/pdf/CBU.pdf
Finally I know what was in the Bullpup cluster warhead
so i'm very happy 
(for AGM-12E there are two options mentioned: (1) a mix of 620 BLU-26 and 210 BLU-36, and (2) 620 BLU-26 + 210 BLU-59)
http://bulletpicker.com/pdf/CBU.pdf
Finally I know what was in the Bullpup cluster warhead
(for AGM-12E there are two options mentioned: (1) a mix of 620 BLU-26 and 210 BLU-36, and (2) 620 BLU-26 + 210 BLU-59)