Sounds like it! I would definitely try to contact someone at the studio to find out for sure. If you don't want to do the Twitter thing, maybe old school it and write an actual letter or email to someone involved in the film. It's worth a shot...
TV Tropes suggests
Before the Crescendolls, Earl de Darkwood's previous victims were famous musicians who look an awful lot like Wolfgang Amadeus Mozart, Jimi Hendrix, Ella Fitzgerald, Janis Joplin and Jimmy Page.
It should be noted that Hendrix was not a trumpet player so I'm suspecting TV Tropes might have this wrong.
In place I offer