Hi Brad,
I did an enormous amount of reading about the trim panel and here is what I came up with:
There were SEs and there were RT/SEs. Since the RT/SE had black in the front grill area, the trim panel was painted Dark Argent Silver on the RT/SEs. Since the SE had silver in the front grill area, the trim panel was painted Light Argent Silver on the SEs.
This is best guess stuff. I have no idea how things were really done way back then. A hint I can give you is that the color of the tail panel tends to show through the hole cut in the trim panel for the trunk lock. Since these very rarely match up perfectly, that can cause some problems. Most people just paint the tail panel behind the trim panel black. That seems to solve this problem.
The trim panel attaches with several clips. (see Marks pics above) If the trim panel was on the car before, there should be several holes in the car that the clips push into and then the trim panel is pushed onto the clips.
After all the research, I finally gave up and decided to paint all the front grill area black and the tail panel black. It was a lot easier and it looks great. This will not work for people that really want to get back to original though.
Added: I got to thinking about that and you should probably put the clips into the trim panel first and then push them into the holes in the body of the car. Mark would know.