I can find pictures of lots of bikes, but not really on cars. From what I've seen, the LED light is a self contained lamp with a clear lens. They cut a hole so the lamp fits in it and they mount it where it's flush. They then use body filler and fill in the seam and lightly out over the lens (mask off the shape you want to keep totally visible I guess) and smooth it where there is no line at all, goes from the metal to the lens and back to metal, totally flush and smooth.
My motorcycle guy cusses them because he'll get parts in that have had the light put in and he does not realize it because they put a light coat of sealer on the bare metal and actually cover the light up. He throws things if he realizes it after he has primed and sanded everything and layed out his artwork, then has to go back and wetsand the lights down where they actually can glow through.
The LED lights I've seen have wings behind them, so you can mount them however you want, either gluing or screwing or however. If that even remotely makes sense at all. Clear as mud and as easy as a monkey humping a football.
