This guy at one point came in a blister with the Champion with Shotgun. He’s shown in the 1993 catalogue as part number 72401/3.
He’s a 1992 sculpt by Jes Goodwin. Here he is in White Dwarf 169:
Undercoat: Vallejo Mecha Black
Zorn palette used: PBr24 (Chrome Titanium Oxide, in this case Kimera Honey Moon Yellow), PV19 (Beta Quinacridone, in this case Scale75 Crimson), PBk-7 (Carbon Black, Scale75 Art Black) and PW-6 (Titanium Oxide, Scale75 Art White).
Armageddon Dunes followed by Goblin Green for the base with a drybrush of Sunburst Yellow, and Scale75’s Black Metal/Thrash Metal/Heavy Metal/Speed Metal/White Alchemy for the metallics.