The Notek Night driving system was introduced onto new made vehicles in early 1940, and at the same time lighting kits were issed for retropective fitting to existing vehicles.
All my original Notek documenation is dated 1940.
This is noticible when looking at photos of vehicles in the Battle for France in 1940, a few will have the Notek system but most do not, after this date of course the amount of Notek systems on vehicles increases rapidly. No doubt the intention was to restrospectively fit the system to all earlier vehciles, but I am sure that there were some that lasted for a long time without ever being fitted with the system.
So the vast majority of Krupp Proetz would have been manufactured without the Notek system.
cheers leonard paul