Fullcapwearer,
All knots are bleached at the factory by default so there is no need to request it. Some hair replacement companies bleach only the front hair line hairs but Toplace bleaches all the knots. The darker the hair the longer the knots need to be bleached to remove the color. So black hair requires the longest bleaching time. Lighter color hair is easier to bleach. Hair wearers tend to inspect the knots much more closely than the average person that sees you.
Regards,
John