In the comics, the Human Target's modus operandi is to use realistic life masks to disguise himself as the target. This aspect of the character was not used in the show due to budget constraints.
Jackie Earle Haley's character is named Guerrero. It's the Spanish word for "warrior". Ironically, Guerrero never fights, using his intelligence and abilities as a counterstrike spy, defeating his enemies without a fight. (EDIT: Guerrero has been involved in plenty of fights. Fist and gun fights. )
Several actors in Human Target have worked with the CW's Arrowverse shows before. Among these are Mark Valley who played Anton Slater, the prosecuting attorney in the case against Barry Allen when he was framed for DeVoe's murder, Courtney Ford who played Nora Darhk in Legends of Tomorrow, Mark Desabrais who has done stunts for Arrow, Supergirl, and Legends of Tomorrow, and several more.