The good deals tend to get snapped up quickly, so they don't leave as much of a 'footprint' as the high priced stuff does (especially the stratospherically priced, but very well documented vehicles on "Bring a Trailer").

As far as four- and six-cylinder Benzes from the 1960s go, there are not too many left that are in good condition, so it can take a while to find the right one. But the good ones are out there, as few as there may be, and are available at a good price to a buyer who is willing to walk.