When driving through the GDR in 1981 Gerd Heidemann and his boss are listening to "No bomb" by Berluc, which was released in 1983. Furthermore: Heidemann's trip to East Germany was in autumn 1980, not in 1981.
In the disco scene, set in May 1981, "Let's Dance" by David Bowie is played, which was released in 1983.