In 1979, Sachs changed the model Balboa's name to Suburban and the Westlake became the Sundancer. These name changes were aimed at the US market. Your Suburban side covers are the same as the Westlake, Balboa, Sundancer and most other Sachs Mopeds.
Here is a link to a right side cover with a Suburban decal on it. We are currently out of all Sachs left hand side covers.
The following picture of a 1978 Balboa. Covers were grey, had Superman tail light, black section of tail pipe, spoke wheels, round cev switches, and only a few other minor changes