From what I've found(
HERE), the GMC Wrangler was a Canadian only model.
Maybe check out
THIS SITE for '73 - '87 Chevy's.
Or you could get in touch with GM and see if they can help ya out.
THIS PAGE says .....
QUOTE
If you are restoring your truck, looking to restore your truck, or just want more information on your truck...have I got a treat for you. GM has what are called "Restoration Packets" for GM vehicle owners. These packets consist of tons of information pertaining to options, specifications, maintenance, and parts sources just to name a few. Best of all...IT'S FREE!!! All you need to do is contact GM (by phone or mail), tell them your VIN, and wait the stated "6-8 weeks" for it to arrive in your mailbox (I got mine in two weeks). Below you will find the number(s) you need to call, or an address if you choose to write a letter.
GM Customer Service: 1-800-222-1020
GM Customer Service address: Chevrolet, P.O. Box 33170, Detroit, Michigan 48232-5170