To correct this, I used some 120 grit sandpaper on the panel for an even finish. I'm going to leave it like this to make bonding the detail pieces on better.
I also had to re-think how I am going to bond the rear skins together. One of the other builders found some very thin 3M tape that is double sided and has the strength to hold the skins together. The tape is 2mm thick and based on what the other builder has posted, is having great results. So, I ordered some! (https://www.rshughes.com/products/021200_13974.html)
In order for the adhesive to work best, it will need to go on bare metal. In order for that to happen, I taped off the areas in which the inner skin is exposed to the outer. Once that was done, it was time to start sanding away the paint and primer (that I had just put on a few days ago!)....