That story seems more or less to be a myth, too. And there seems to be a good reason why they used from pencils, which they used in the beginning to pens:

"Pencils may not have been the best choice anyway. The tips flaked and broke off, drifting in microgravity where they could potentially harm an astronaut or equipment. And pencils are flammable--a quality NASA wanted to avoid in onboard objects after the Apollo 1 fire."

https://www.scientificamerican.com/article/fact-or-fiction-n...