In Wrath of the Lich King it is item level 251 and requires level 80. In MoP Classic it is item level 251, requires level 80 and sells to vendors for 1c.
Read from the World of Warcraft client build files.
How Relentless Gladiator's Kodohide Helm Compares
Who It Suits
Leather is the armor type Demon Hunter, Druid, Monk and Rogue wear. With Agility or Intellect, Relentless Gladiator's Kodohide Helm suits Assassination, Outlaw and Subtlety Rogue; Brewmaster, Mistweaver and Windwalker Monk; Balance, Feral, Guardian and Restoration Druid; Havoc, Vengeance and Devourer Demon Hunter.
Items Numbered Next to Relentless Gladiator's Kodohide Helm
Blizzard numbers items as they are created, so the named items next to ID 41322 (41316 to 41328) were usually added in the same batch as Relentless Gladiator's Kodohide Helm: the same quest line, zone, vendor or reward set.