James Bamford announced via Twitter that he appeared in front of the camera on Arrow today. James has appeared on the show several times, most famously he played Gunman #2 in The Pilot, whom Oliver chased and broke his neck. Could Gunman #2 have been resurrected by way of the Lazarus Pit? It may be more likely that James is reprising his role as the Boxing Referee or maybe a new character.
Either way, fans of BamBam are very excited to see him perform on screen.
UPDATE: Definitive answer from James. No, Gunman #2 is not alive. The episode in question is 320.