To what extent? The number is 2.9 http://www.businessinsider.com/eric-barker-millionaires-bad-...
However, this just shows that they are outliers. It may turn out to be the case that there are just as many negative outliers for that GPA (or not, I don't know).
If you are asking if it is true that this is an old saying, I have heard the sentiment before many times. I can't remember the name of the book where someone said the people who got the to the moon were lead by a C-student but all of them had perfect GPAs. However, I don't know of that particular phrasing.