Yes, values depend on caliber. This is from Fjestads Blue Book;
In 95%:
PPK/S .22 $550
PPK/S 7.65mm $375
PPK/S 9mm K $495
These are for Walther-marked models.
Manhurin prices:
PPK/S imported '84-'86 95% $275
PPK/S imported resumed in '88, 95% $320
Values reflect number imported and amount manufactured.
PPK's will always be higher since they are banned. Same with the TPH.
These values are two years old. They have increased a bit. I loaned my new copy out. If anyone has current values, please post.