Mal, the Titan in training, is flung into the past when an experiment of the Titans' mentor, Mr. Jupiter, goes awry. Kid Flash uses a cosmic treadmill to rescue him. But, having inadvertently let a caveman die and so changing prehistory, they return to an alternate, medieval-style 1971.
The telling sign of Haney's taking over the script is the florid verse that "tells it like it is" atop page 16. There are more subtle things: the interjection "hunh," used twice in the first half, I've seen Skeates use all the time, but Haney never; whereas "A split instant later'" on the last page, is used elsewhere by Haney, but not Skeates.
The less quantifiable but very obvious difference is the speech patterns. Haney returns the Titans to his earlier issues' patented "hep," "with-it" dialogue. His dialogue makes much of Mal's being black. In fact, I think Haney takes over the scripting with page 15, the point at which Mal starts mentioning the ghetto, which continues in the next issue. The younger Skeates stays away from the obvious character tags:
So Bob Haney did roughly the final third of this story. Even the credits in a particular issue may not always tell the whole story.