I know this is an older thread, so I don't know if you ever found out the info on the baseball game. However, you piqued my interest when I came across this last night, so I GOOGLED: "Eagles band infamous baseball game:"
Click on the 2nd entry entitled "Eagles articles." There's one written by Glenn and Don entitled Eagles Land on Rolling Stone that goes into all the fun details. There looks to be a few other articles about the same, I just didn't have time to read the others. Enjoy!