I was an Air France FA ("Steward") on B 707s during my 3 college summers of 1969,70,71.

The first 2 years, they had the hat racks. The first 747 came in 1970 with the bins and by 1971 the 707s were re-equiped with "bins" which were not much more than the old racks but with doors and sliding locks.

Just as an anecdote, I spent many nights removing from the hat racks
babies on blankets which their parents had put up there to sleep.