Are those engine bay mounted intercoolers standard on vw golf gtd's?
No. There was a 70-hp GTD and a 80-hp GTD, the latter having the intercooler, different injectors and a bit more boost.
Both were also available in non-GTD models, ie. CL, GL etc.
Note that if you use the stock intercooler ( engine bay -mounted ) you absolutely have to have the original plastic baffles and stuff, or at least custom baffles. Otherways your I/C will get heat soaked all the time when hot engine room air gets to it from all sides. A good cold air feed also only works right if all the sides of th I/C are properly sealed.
An electric fan would be nice too. A 'pulling' tyoe fan mounted below the I/C would make a difference when used with a proper cold-air feed. Experience tells me a good fan can almost replicate FMIC performance.