Thanks Kevin!
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I believe it's a late 60's model (grew up with a '67 model and it still had an impeller!). I am going to do some hunting for Eatons appliances and see what comes up...
D&M stands for Design & Manufacturing - they built some basic design appliances and branded them differently. I am only familiar with what dishwashers they made, starting with the American Kitchens Roto-Tray and going through the late 50's and 60's with brands like Admiral, Kelvinator, Westinghouse, and even some Kenmores.
Hope that's not too much information!! LOL
The turquoise square is indeed the detergent cup. Just like the one we had when I was a smartass punk kid! Oh, and this is neat, the water inlet valve will position over each of the detergent cups for filling. If you select the single wash option on the timer, the inlet goes over cup 1, and if you select the double wash, the valve starts on cup 2, then clicks to cup 1 for the second wash!