80s and 90s china pencil collector diddling. I would do it too. It made the markings stand out for pictures back in the day when there was no internet, no digital professional grade type cameras, and such, and we had to mail each other pics. Back then some guys would polish buttplates and stock disks to a blinding mirror brightness too, and the worst vandals would clean laminate stocks until they were screaming blond and "new" looking.
Today, any of those things, including china pencil white in the numbers, is like flying a douc4bag flag on a graphite rod on your banana seat bike.