The 85 with the gray interior had a two tone dash with the lower half being a lighter color commonly called Dove Gray. It matched the vinyl of the door panel, the rear most portion of the console, and the interior hard vinyl trim. I believe the 84 had the same interior color combination, though you do have the elastic map holder that was common only to the 84. 85's had a pocket.
The wiring system was much better on the 85's and easier to do a conversion. You also mentioned that the harness attached between the battery and passenger shock tower. The 84 attached to the back of the passenger compartment. The 84 also had glass quarter windows. Later years were plastic.
The 84 had some features of the electrical system that were common only to it. It had a 2 speed cooling fan identified by a 3 wire harness, the AC system was different, I believe the wiper system was different, and there were some other differences.