It didn't used to be. I've used obj the other way round to get GG stuff into Blender on occasion, but as far as I know you only have X and FBX to load into GG and I'm not sure how good FBX import is at the moment. You would have to convert your obj model into the best option of the two.
SPECS: Ryzen 1700 CPU. Nvidia 970GTX. 16 Gig Memory. Win 10.