Doug,
the production number is an assembly-line scheduling number and is repetitive (rolling over, and/or starting at 1 every new year). The car's serial number is not 000 001 (some documentation of that car is in our Technical Manual, under Data Cards, Vehicle Identification Number).
John Mancini,
the Body and Paint Number Plate Jon M (717-113) shows in his photo above also shows 5 as market designation, i.e. the car was originally sold in Europe except Germany. Jon's profile does not list where he resides. But the car could have been sold and registered for a long time in a country where mother-in-laws are usually transported in the trunk or softtop-compartment. Since I don't want to step on anybody's toes, I'll not suggest any country.
Klaus
1969 280 SL