Legend says Ralph Hofer was shot down by Erich Hartmann, but since "The Kidd" went down over Hungary and Jg-52 was flying over Romania at the time, I don't really buy it, though Hofer was in fact the only 8th AAF ace to go down in a2a combat and not to ground fire.
Oops, the 4th FG had at least 5 aces down in air to air that I can think of including Carpenter, Sobanski, McGrattan, Bennett, Edner, Lang plus McPharlin (339) who was a 4th ace flying with 4th on D-Day when he was KIA w/Sobanski and McGrattan - three aces in one flight, and one fight. I could dig up more, perhaps.
Adams and Browning for 357FG come to mind, there are more there also. Mahurin was shot down by Do 217 gunner.
I also don't buy it for the simple overly-coincidental aspect of two young aces both called "The Kid" (well, "Bubi", but its the German equivalent) meeting in the air and fighting to the death. Plus I think the story would have made it into one of Hartmanns autobiographies, not just confined to books on the 4th.