End of the Fedora era
I believe this marked the end of the true 1960s.
I just saw this again, and I'll have to say this movie has to be the last one where brill-cream haired men still wore fitted three-piece suits with skinny ties and fedoras. 1968 would probably have been just about the end of that style era before sideburns, wide lapels, and fat ties made their appearance.
As for Fay Dunaway, maybe a bit too much eye makeup, but otherwise she looks terrific in this one. Sexy as hell.