I’m not sure where Dirty Harry got his information, but the 9mm kurz (.380) version of the PP and PPK in any variant was never issued to law enforcement in Europe. The 7.65mm (.32) was the universal police round with those countries that didn’t stick with the 9mm Luger after 1945, and except for a brief experiment with the 9mm Ultra (PP Super) in the 1970s in a few states, everybody was back with full-size 9mm pistols by the early 1980s.

European law enforcement post-war did prefer steel frames. The PPK-L was acquired in limited numbers for special applications; for example, the Swiss armed their sky marshals with the PPK-L in .22. The German army issued both the PPK and PPK-L version as the P21 in 7.65mm, the PPK-L mostly being issued to pilots and such where weight was a prime issue.