Oh, they will....just wait till Friedrich will come on-line later today!!
As to verifying claims so long after the event; Of course it will prove impossible to positively ID all claims and such. Sources do prove not always reliable. For example, 381BG lost 8 planes on January 11, 1944. These came down in a wide area. But the MACR's all state that the time they were last seen by any other in the formation was 11.22. For all 8! So, yes, research never ends... The records for 447BG are virtually non-exsistant. They lost three planes but all their operations officer could write down was the fact that three planes were MIA. And he added a list with claims of LW fighters. If this list is correct the 447th gunners were responsible for the downing of all LW fighters that day and then some....
As to Schnaufer's claim; I wonder what you would need/what would constitute sufficient evidence, but I am positive that you are closer to ID-ing this claim than whoever. I feel that it is "with a probability bordering certainty" that Schnaufer downed
J-Johnnie. (Although I know there are people who will contradict me...
)