That looks like a 1950s-vintage portable. Positively jet-age styling. Also, that was a very popular color for Volkswagens.
From what I can tell, you're right - which puts my 40 year old estimate at about ten years short. ;-) Well, almost.
The guy who was selling it said "circa 1974". and I knew that was wrong - the pictures I found of the version of this model from the 70s were much boxier and the "Olympia" name was in a square font instead of that script look.
Found the serial number and looked it up, and it appears it was made in 1958 - one of the first years they even made this model. Kewl. Considering the condition it's in, it doesn't make it valuable - especially in this country, where I'm guessing the German keyboard layout counts against it (probably why I was the only bidder!) - but it's neat just the same!
Looking it over, there was a little sticker under the ribbon cover that had some initials and a November '74 date, which must be what he'd used to guesstimate. I'm guessing it's a maintenance marker. It would have already been 16 then!