Building a model is just like owning a real car, you can do whatever you want with it. I have seen a lot of car back in the day that had weird, funny, awesome and outstanding paint jobs. The overlook on the trim could be just someone wanting to have it painted. Back in 81, I had my 72 satellite bumpers and all the trim painted semi gloss black with a gloss black body. It looked really great.
You did a great job on your model. Black cars always look awesome, trim or no trim.