Someone I know who went to Berklee in the early 90s said that it was a required text for certain jazz classes, and you had to buy it from a bootlegger.
Your friend was there close enough to the time that I was there that it was probably the same thing. There was "a guy" that hung out around the school... I'd usually see him somewhere around the intersection of Mass Ave and Boylston... And he was known as the guy to talk to if you wanted a real book (and probably other stuff as well). Every once in a while you'd see him just running off down the street like he was being chased or something (never saw a pursuer) though it was said every once in a while they'd try and busy him.
I didn't actually get my copy from him ... My high school band teacher was a pretty accomplished bebop guy that burned out playing in the house bands in Vegas and "retired" to teaching.... So he hooked those students of his up that had an interest in small group playing or gigging. So had my copy before going to Berklee.