Thought much of Deutschland 83 was amped up to a large degree, that particular scene rang true to me. "Nostalgia" for the National Socialist era was quite common; though I'm not sure "openly discussed" captures its essence.
The West German state (and later unified Germany) put in place numerous laws to prevent open adoration of the era: nazi symbols, the swastika, giving the "nazi salute", saying "heil hitler" are all illegal and carry a potential punishment of many years in prison. Yet despite this, a sizable minority looked back fondly on the era.
Here is a short article from 1981 noting that fully 18 percent of Germans felt that Germany was better under the Nazis. Also note how alarming this news was to Helmut Schmidt and the government; they kept the results under wrap for a year. It's hard to say definitively that fondness for the era was discussed "openly," but I think the best way to describe it would be similarly to the way a portion of modern Americans would discuss racist views. They generally keep them to themselves, but in an environment with others with similar views they'd be discussed openly, and they also frequently come out regardless.
Edit: for some folks in Germany, the war has never ended : ) https://www.youtube.com/watch?v=crQ4llWDl0Q