A report that tells you your Mercedes was built in Germany isn't much of a report :p If you provide some specifics of what car you have, folks can help you determine whether or not it was built to US specs. That will help you determine whether or not it should have an EGR system.
You mention that it has an OVP. I believe any car with an OVP relay should have an EGR system regardless of where it was intended to be sold.
Yes, I know that MBs are built in lots of countries.
81 300SD (on ebay)