100-340
The Walther P1 is an aluminum framed, post WWII version of the German P-38. They not as collectable, or as valuable, as a P-38. 100-1000 USD
See Dieter Marschall's book Walther P1-99
Complete description of ALL markings.
100-2000 usd
100-300 USD
50-500 USD
depends on what glock if it is a 9mm i would go with the walther but if it is a 40 s&w then i would go with that glock 9mm are proven not to kill as good as other handguns and maybe not kill at all for home defense but for fun take the walther p99
9mm and 380 use the same diameter projectile, .355 inch
Depending on condition, around $800. And that is 9mm Kurz (German for short)
100-1000 or so
Only if it is the same type. There are different types of 9mm and they do not interchange as a rule. For example, the Walther PP fires a .380 ACP round, known as 9mm Kurz. This cartridge is shorter and not as powerful as the 9mm Parabellum, also called 9mm Luger.