I think it would be worth it to send a letter or make a call to the pawnshops within a few miles of the theft. Just think how many items there must be on the list which goes to the whole nation.
I have read that criminals don't like to leave familiar territory. Chances are, if they take the instruments to a pawnshop, it will be a pawnshop nearby.
Also, a pawnshop in an iffy neighborhood might not be among "the 90%."
You have my sympathy. I know how bad I would feel if I lost my instruments.