Here it is. All finished. Tonight, I masked off that tylenol shaped gap above the thumb trigger and painted it black. I also cut and applied the strips of mirrored mylar. One piece of reference material I found showed a little faux trigger made out of the same mylar, so I included it on my build. I'm not totally sure if it's accurate, but it looks neat.
Next up, I need to finish that Batarang.