If it is stainless steel then it is not a European made Walther. Interarms had a license to produce a PPK/S in the US as early as 1978, the first stainless pistols came a few years later. I have owned a couple of the Interarms US made PPK pistols and they were good performers with good quality ammo, reloads would usually cause problems in mine.

In my opinion the PPK/S that you describe is a good deal for the price, I have noticed that these have started to go up in price when found around here. I think the increase is due to the rather poor performance with the current generation of S&W made PPK series, and the european made pistols are considerably more when found for sale.