Remember them being very basic aftermarket elastomer forks unless they're a more advanced version. The ones I'm thinking of were yellow with forward set drop outs. Cant imagine them being very serviceable, more a fit and forget then replace fork.
I do not remember exact model, but I serviced Freinds of min Duotrack a while ago
Very poor inside, so it shouldn't be any problem with servicing
few pics and info here (You'll need to transale it) http://forum.retromtb.pl/viewtopic.php? ... =duo+track