No. On GamersGate, click on *system requirements* for DLCs and it will usually state whether it is compatible or not with a core game purchased elsewhere. Such it says the DLCs are only compatible with the GG version. This feature should be used when buying main games as well in the future. GamersGate has inconsistent limitations at times (and none at other times) -- imposed from outside I'm sure -- as much as I like the place.