Pretty Boy the original was a handsome guy
This guy not so much
Original killed or participated in over a dozen killings mostly law men
Pretty serious even if a generous bandit
There are different tales as to why he was nicked name "pretty boy". I read one that basically said the name was given because he dressed nicely even while working on an oil rig, like a "pretty boy", not because he was so handsome.
Gangster tales are to be taken with a grain of salt.