There is no way to find information from Mali government or Mali philatelist because in 1969 it was very hard to contact and communicate like I did for BOGUS Germany 2009 Gandhi special cancellation on personal/customized stamp from Winneden Germany.!!
Also chance of archival of any data from Mali government will be impossible.
Let me know if you have any information about Gandhi Mali 1978 first day cover so I can update my blog after throughly verification of information provider.
Would you trust Gandhi Handbook for your collection ?
My personal opinion is " I don't trust Gandhi Handbook" because it don't have enough written information about philatelic material mentioned in the book as chances of Bogus and Forgery material might have been published unknowingly.
Philatelic Handbook can be trusted ?