BTW, I also have the Kodansha & the Kappa reprints (I assume they are the same as what you have). The Kodansha were 8 volumes of HB books, while the Kappa were Soft cover having some 6 volumes of 90 or so pages in each of 5 sets. There are similarities between the Kappa & the Unit1, but there are differences also, mainly in the dialog, but many panels were cut, others were rearranged in sequence. I painstakingly transcribed the versions I have, which, included the one in Unit 7, "Space Travelers" so named (in English) by Tezuka himself. I 1st compared the AMBASSADOR ATOM in unit 1 with SPACE TRAVELERS (unit 7), then SPACE TRAVELERS with the Kappa version. At this time, I realized that in the COMPLETE WORKS version, Tezuka was talking about the original & the Kappa version, when saying that he had made atom the main character. I do not know how the unit7 version fits into the history.

Here is a listing of the contents I have in the Unit1 set:
I cannot recall any big differences in the stories, without checking my notes, but there are quite a few.

Can you read Japanese, ASTROBUDDY?