When the German Army occupied Athens, all ammunition production by the Greek Powder and Cartridge Co ceased and the facility was converted into a repair facility for mostly light armored vehicles. After the war, they began manufacturing ammunition again. I visited the plant in 1976 and was given an excellent tour by the senior manager, a retired Greek Army general. The plant I visited was manufacturing small arms ammunition through .50 Browning in all the normal calibers. Most of the equipment was US made, I suspect ex-WWII equipment, but some was German made from before WWII, so likely at least some of the equipment had been stored during the war. There were two small lines loading 45ACP on German pre-war equipment. The technician running the lines had worked there before the war when the same equipment in the same location was used to load 9mmP ammunition. He also talked, through a translator, about working on German armor vehicles during the war, and then helping set up the pistol manufacturing equipment shortly after the war and making 45ACP. He confirmed that the company had not made 9mmP ammunition since 1941.
This info is consistent with the production dates above. According to Wikipedia, Athens fell on 27 April 1941.
Hope this information is of some help.