In The Burning Crusade it is item level 123 and requires level 70. In Wrath of the Lich King it is item level 123, requires level 70 and sells to vendors for 1c. In MoP Classic it is item level 123, requires level 70 and sells to vendors for 1c.
Riptide DaggerID 223179 · Weapon - Dagger"The blood will flow freely from your enemies with this dagger."
Items Numbered Next to Gladiator's Shiv
Blizzard numbers items as they are created, so the named items next to ID 28310 (28305 to 28315) were usually added in the same batch as Gladiator's Shiv: the same quest line, zone, vendor or reward set.