Interesting. I was under the impression the first model was a '59 after Olympia's acquisition of Brunsviga.
If the Database is correct AND those serial numbers are accurate, it appears that only 53 machines were classified as '58 models. And for several years they were produced in relatively small numbers. The chart you posted doesn't reflect that the first models were the SGE10, SGE20, and SGE30.
I don't know if any of these were exported at the time, but I've certainly never seen one pop up in my area.