First: Neat guitar! I have a 1982 Destroyer II, but unfortunately I'm going to sell it next week (I don't have time to renovate it, someone else has and he's better off with it...)
If I were you I would try the discussion board of
http://www.ibanezcollectors.com/
Jemsite is more about the modern Iba's, Ibanezcollectors about vintage ones, It'll take a few more days but I'm sure someone will be able to help you out there!
If you post the type of neckjoint (bolt-on or set neck) and the serialnumber it would certainly help!