What? No. You did not have to be a member of the Nazi party to work or serve in the German military during WW2. The Nazis, despite their boogeyman image, were just a political party. They didn't have universal support in Germany. Hell, Hitler was only in power because he got about 51% of the vote. While certainly quite a few of them were members, it was far from a requirement.
At it's peak the Nazi party only had 9 million or so members. That is faaaar from being everyone who was in Germany that was working or serving in the military.