I can see where the 'rumour' came from:
"Because of a ballpoint pen's reliance on gravity to coat the ball with ink, most cannot be used to write upside-down. However, technology developed by Fisher pens in the United States resulted in the production of what came to be known as the "Fisher
Space Pen". Space Pens combine a more viscous ink with a pressurized ink reservoir
[4] that forces the ink toward the point. Unlike standard ballpoints, the rear end of a Space Pen's pressurized reservoir is sealed, eliminating evaporation and leakage,
[4] thus allowing the pen to write upside-down, in zero-gravity environments, and reportedly underwater.
[26]Astronauts have made use of these pens in outer space.
[4]"
I'm sure somebody would have then said that it was just the sort of thing NASA would produce, then it's difficult for the truth to get in the way of a good story!