Hello Wayne,
unfortunately, I have not found any information that indicates a continued production of the EKT models after the company was incorporated into the VEB "Modell- und Plastespielwarenkombinat Annaberg-Buchholz". For me, the trail gets lost. As far as I know, the Volkseigene Betrieb (VEB) Modell- und Plastespielwarenkombinat Annaberg-Buchholz was broken up into several parts and sold in the years 1989 - 1991 by the Deutsche Treuhand, an organization that was supposed to wind up, dissolve or sell "non-economic" GDR companies. Some of these companies are still producing today or have been sold again or are insolvent. But there is no trace of EKT anymore. Looks like the production of the EKT models really ended in 1972. An end in the fog.