Interestingly, he also reports:
The /S version was created by Walther to meet the new ‘sporting purposes’ importation requirement under the 1968 Gun Control Act. ‘S’ stands for Sport, and the frame is taller – i.e., the grip is longer – than the standard PPK. That actually makes the pistol a bit more pleasant for target shooting and plinking, as your otherwise-dangling pinky has a home. Probably a good choice for the .22 version, which I’d assume won’t be a popular CCW option where the extra size or weight would be less desirable.
In the black plastic Walther case, along with the PPK/S, is a 10-round magazine, a gun lock, an owner’s manual, warranty card, an NSSF safety pamphlet and a ziplock baggie with some parts and tools in it. Included are two replacement front sights – one taller and one shorter than the sight installed on the gun – for adjusting point of impact for elevation, a thin punch for pushing out the pin in the front sight, an Allen wrench for adjusting the rear sight for windage, and a wrench for removing the barrel nut. All in all pretty good kit, although I wouldn’t mind a second magazine. They’re available online for around $28.
At the front of the barrel, a nut can be unscrewed in order to remove the barrel from the frame. Another reason to remove that nut would be to install a thread adaptor. For instance, to effectively extend the barrel out the front of the slide and provide 1/2×28 threads for mounting some sort of muzzle accessory like a compensator, fake suppressor for the easy secret agent look, or real suppressor to more fully satisfy your inner Bond. Thread adapters for Walther’s P22 fit the PPK/S just right!