oops, I went back to listen to what I heard yesterday, and it turns out flight check76 wasn't a P51 but there was one flying around when I switched over to listen to JFK departure after flight check 76 flew over 4R (at 1314:38), then when the controller told fight check 76 to contact NY approach he then told JB 1305 to look out for the P51 - silver and I thought he was referring to flight check, but I was mistaken. When I went back and listened to departure, he was talking to the P51 (with the 337 fighter squadron) just before flightcheck checked in (at 1314:17). Sorry, I guess that's what happens when you jump around frequencies, you can't always trust everything you hear.