It was once thought that giant ground sloths were important for spreading avocados, but that seems to have been a mistake. Anyway, that was long after the dinosaurs. Flowering plants in general were still pretty new by the time the dinosaurs died out. I bet an actual dinosaur never saw an avocado. :)

Edit: transcript of a video about the sloth/avocado thing: https://nerdfighteria.info/v/jpcBgYYFS8o