Pistols are generally not issued to riflemen. More typically they are issued to officers, and sometimes artillery troops and rear-area troops as well. This is because the pistol's primary role is personal defense, and a rifle might interfere with their other duties.

Production of the P08 "Luger" ceased in 1942; it had been supplemented by the new P38 starting in, you guessed it, 1938. The P38 was far easier and less expensive and, most importantly, quicker to make. So even at the start of WWII, the Luger was already on the way out. More importantly, the only troops authorized pistols in the German military were machine gunners, heavy weapons crewmen, other specialists, senior NCOs, and officers. So if you're expecting to see a minority-issue handgun showing up regularly, you're already in trouble.