The 84 never had a plaque either. I don't remember when they stopped doing that, somewhere around 74-76, I think. You can still buy the plaques to put into whatever you want though. It's clear that he has customized an 82 to get the look that he wants. It is a badge that is between the LED tail lights which are also not stock. He did say that he removed the emblems, logos, and stripes (and obviously the side markers) to make a very clean looking shape.
I guess it's important to note that the guy never does tell us what year the car is, so technically he is not lying. The error would lie in the person who posted the video and made that mistake in the title. Not really a big deal I guess, it just bugged me. lol.
I've spent too much time picking this video apart and now that I've watched it five or six times, I'm going to stop complaining about it and give proper kudos. It is a well put together video with some beautiful scenery and roads, nice music and transitions. It really is a great video and a beautiful car that this guy obviously has a lot of love for. Good for him, and thanks for posting it up Nik!