Most guys back in the day ( if you lived in a city) did some boxing. There was a boxing club on every corner. I am inclined to be skeptical of Scarfo's boxing skills.
Boxing has absolutely no barriers to entry and is very easy to become pro and create the illusion that you are a skilled fighter.
Look at chuck zito who claims he was a golden gloves fighter.. big deal!!! Anyone can enter the gloves. Did he actually win the gloves.? No