According to the ETO USAAF Victory List, Kocienki was awarded a Bf 109 that day at 2120 hrs at Cloyes.
So if there is a trace of this collision in German documents, it should be searched in a battle in the evening of that day.
III./JG 54 pilots claimed four P-47s and a P-51 at the right time (if both sides then used same hour, I have not checked it) and in the same general area.
Statement of Kocienki's loss (by the way he is still MIA) can be found here:
http://www.510fs.org/wwii/killed-in-...slaw-kociencki
This statement says that he was making a frontal pass with a Bf 109 and both were seen to crash, the P-47 losing part of its wing, but no collision is actually described.
III./JG 54 suffered no known loss that day.