At some point prior to 2281, Big Beard and Little Beard came into owing a debt to Carlitos Wayne, though it's only known that it involved their beards.
As partnered guns-for-hire, Big Beard typically acts as the one to talk to, based off who has the bigger whiskers.
Bye Bye Love: Carlitos asks the player character to recruit Big Beard and Little Beard as additional muscle for helping get Joana and her friends out of Gomorrah.