Re: Walther PP 7.65
That gun was made in 1962, so it is post-war and has no historical value. I know some folks seem to think any Walther PP or PPK is worth a bunch of money, but that gun has seen some use and wear and I would value it at around $350 retail. (That is what a gunshop would sell it for, not what they would give you for it.)
The lack of import markings would indicate it was probably purchased in Germany or in a country other than the U.S. Also, the cancelled marking appears to be a police stamp, indicating it was a used police gun sold as surplus on the market. I don't know what ByP stands for (Bayern Polizei, perhaps), but the marking is like that used by the German police.