Kurtl your stampings on shells mean:
3 cm shell - manufacturer: Polte, Poltestr und Fichtestr. Werk Magdeburg (aux), Sachsen-Anhalt, production date: 1944 (44), lot number (98 )
2 cm shell - manufacturer: Gebr. Junghans AG, Schwenningen (htq), production date: 1943 (43), lot number (30d)