I love it when I buy a collection and find unusual items in the bottom of the box. Here are a few. The 364C with the red slide is found on occasion. Next to it is the 390C with the red slide which I rarely see. While they look identical from the outside they have different numbers stamped on the back and they are wired differently. Finally I have a 153C controller with a red insulator. I have never seen another one in 35 years of collecting but I am sure they are out there.
Al