Is the rear valance the part you're calling the rear finish panel?

On my car, I put the tail lights and tail light panel in, then the rear bumper and then the rear valance. If I remember correctly, you have to have the valance off to access the bumper bolts easily. If the exhaust was done while the rear valance was off, it might be installed too high and will need to be dropped down to fit the valance in above the tips.