Shelby GT350 Mustang, with a couple strange things about it

What is this 4 knob device? Speaker controls? Power amp for the stereo?

 and when the sign on the dash said the car was still owned by the original owner, but I saw this temp registration in the back window, I wondered what was going on...

I still can't figure out why it's an 1988 Nissan listed on the temp.