Bugner by decision , competitive at times. Something like 8-7 in rounds . Perhaps Ingo scoring a kd early but losing control of the fight later. In the latter rounds Ingo becomes defensive , looking for one last right hand but it never happens.
If he’s in his prime and in good shape, I’d lean toward Ingo on points, who might be a bit underrated here. Beyond his big right hand, Ingo was also a solid boxer. He didn’t have a great chin, but I don’t think Bugner would knock him out. Well, Bugner had the better chin, but that doesn't mean Ingo's Bingo wouldn't be dangerous to him. Overall, Ingo was more success-proven, with a better amateur career, including an Olympic silver medal. He also beat better fighters than Bugner, such as a prime Patterson in their first fight (and was close to winning their third fight as well) and Machen. Bugner, on the other hand, never beat anyone as good as a prime Ingo. The best opponent he beat at the time they fought was perhaps an aging Henry Cooper, whom he defeated by a controversial points decision (Ingo had stopped a young Cooper in five rounds). Nothing against Bugner, who was a good fighter… I just favor the overall more proven and cagier Ingo here, who I believe could hold own against Bugner even in a longer fight (as seen in his bouts against Joe Erskine and Franco Cavicchi).