80, 90 designation?

[dneider@prairienet.org (David Neider)]

I have a 1988 90 q that has grey cloth interior. I thought all 90's had a 
leather interior the plaque on the car says that it is a 90, the VIN 
indicates that it is an 80 and the owners manual is for an 80 also the 
bill of sale says its an 80 ?has anyone had this same? Also why is the 
wiring harness missing on one of the rear fog lights. The 
temperature gauge also intermittently works what is wrong?