That would figure, Little Hawk. Bob probably got it from Steve Goodman.
Hildebrand sang it around Boston at the time of the incident. People often asked if they could record him and he always was quite happy about that. He also wrote out song words for people. Steve may have heard Hildebrand sing it, but he would have been very young at the time. It's more likely that he heard somebody else sing it or heard it on a private tape. Hildebrand left Boston, dropped out of university, and went off to Europe. It seems the song took on a life of its own and stayed alive mainly because of Steve Goodman.
It's fun being a part of an urban legend - if only a very minor one. Joy