according to the wikipedia article the book that the sheik has read are changed twice. I assume that this means that the picture with the Congo book was in Le Petit Vingtieme and picture with the America book was in the 1934 book?
In the black & white version - both PV and book - the sheik was showing the most recent book, i.e. the black & white version of Tintin in America
. In the colour version of the book from 1955, this was changed to Tintin in the Congo
. However, there are several versions of the colour book with minor changes, like the map and dialogue on page 1 (about an Asian trip in some versions and a Mediterrean trip in others) and an early edition mistake on page 52 where Snowy is present by Tintin's side in the palace (although he still was with the Thompsons at that time, so Snowy was removed in later editions). I'm not sure about the chronology, but when some of these changes were made, Tintin in the Congo
was also replaced by Destination Moon
on page 15.
There are still some inconsistencies left though, like the position of Snowy in the last two panels on page 16 and up-rolled sleeves on Tintin in one of the panels on page 31.