I emailed and called the attorney representing the plaintiff, gave him enough information to find out who was who.
Counsel had already developed a lot of leads, so maybe they'll know the score pretty soon.
Funny thing is, "the guy who gave us grief" works just a few blocks from the Guadagnini Violin Shop.
1+1=2...I guarantee it.
[EDIT / UPDATE]
According to the shop owner, with whom I have corresponded by email, this isn't the same dude, but the responsible party has been identified.