TM-Frank said:Mabe they refer to the fact that GasGas radiators are produced by KTM. There are three branches of KTM - motorcycles, bicycles and radiators - each an independent company. Link to the radiator branch:http://www.ktm-kuehler.at/
The mounting points are more or less the same on every radiator they make and they supply nearly all of the european bike brands with their radiators. So you could mount the radiators from any KTM (or TM or Husqvarna or whatnot euro-dirtbike) to your GasGas, but you'll have to be very creative with the waterhoses, because the radiators vary very much when it comes to where the connections are placed.
Maybe there really is a KTM model with 100% identical radiators as your '99 GG, but I really doubt that.