Sam, what have I here ?Vince...the plain bottoms are post war. the P.Mod 27 are wartime . the serial numbered ones are iffy. some are actually pre-war CZ24 mags that people mistake for CZ27 mags as the .380 mags fit in the .32 cal gun. a lot of times you will even see CZ24 mags in a CZ27 and vice versa. That is why the Germans then also marked the bottoms of mags they produced P.Mod 24 and P.Mod 27 becuase the CZ24's were still being utilized. then you still have the CZ27 that were issued to police and then those did get serialized to the gun. so, my guess is in your pic you posted you have a CZ24 mag. the best way to check is at the tops. the lips holding in the shells will be wider for the 380.