In Wrath of the Lich King it is item level 226, requires level 80 and is named Dreadnaught Legplates. In MoP Classic it is item level 213 and requires level 80.
Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Valorous Dreadnaught Legplates Compares
Who It Suits
Plate is the armor type Death Knight, Paladin and Warrior wear. With Strength or Intellect, Valorous Dreadnaught Legplates suits Arms, Fury and Protection Warrior; Holy, Protection and Retribution Paladin; Blood, Frost and Unholy Death Knight.
Transmog Sets
Valorous Dreadnaught Legplates is part of the transmog set Valorous Dreadnaught Battlegear (Warrior only). The other 16 pieces:
Items Numbered Next to Valorous Dreadnaught Legplates
Blizzard numbers items as they are created, so the named items next to ID 40529 (40524 to 40536) were usually added in the same batch as Valorous Dreadnaught Legplates: the same quest line, zone, vendor or reward set.