No, he reasons that it must be humans because why would a completely alien, 5th dimensional race give a damn about some primitive lifeforms on the 3rd planet of a minor star in a minor galaxy.
Post-humans are conjectured by Cooper to be a 5th dimensional race. (Post-)Humans would be very interested in setting up the events in the past(woah slippery slope) that set the stage for the eventual emergence of post-humans.
