I have a vivider memory of working on the song at a Worldcon in California -- which was either ConJose or Aneheim, and I'm thinking it was ConJose -- whatever first the one nightface came over for was. I'm quite sure I wasn't -at- the Boskone in Framingham as far bask as 2001; you're probably remembering a significantly later con (maybe the 2004 worldcon, the Boskone Done Large?)