I found a couple of places in the trading post wrecking new corollas. King wreck 029721 0023 and On Boost auto spares in Bankstown 029709 2992. Its not much to go with, but i hope it helps.
If you can't find any decal then your hilux is built in or after august 03. All hilux built between sept 2002 - july 2003 ( engine 3rz-fe ) are lpg compatible. For the Hilux built between august 2003- jan 2005 , only the 4cyl, 4x2 are compatible.