Rust on the flywheel, while unsightly, rarely affects performance.
Pull the flywheel, under it there might be a cover, with the ignition points under it. Or, it may have a solid state setup.
At least with points, you can diagnose and repair. With SS, you simply replace the module.

__________________
1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags