to my knowledge as a matter of fact there is no formal regulation about the wear of East German awards.
What I know though, is that awards of the following institutions:
Ministerium für Staatssicherheit
The wear of any East German award on Bundeswehr uniforms is also forbidden.... so for example service medals, which were a kind of award that was given automatically with the proceeding of the service years, are not allowed.
The difference between III. Reich awards and DDR awards and the legitimation of the former ones through the regulations of the Odensgesetz of 1957 is that the III. Reich awards were mostly given for bravery, heroism, war actions a.s.o. as a distinctive sign of the valor of the soldier........
More detailed information can be found by searching " Deutsch-Deutsche Rechtszeitschrift, München 1995 von Enno Bernzen und Klaus H. Feder" in this link http://www.ordenstraeger.de/de/literaturhinweise/
or proceed directly to the document clicking this link: http://www.feuerwehrgeschichte.de/geschichte/ddr-auszeich-tragen.htm