I don't know the answer to the above questions, but I'll take a stab. I THINK the gt200 and bass 200 are the same thing. I know you can get gt120's and 100's for geetar, but I've never seen a gt200 marketed for guitars.
As for the whole green thing, I think it was some guy from Fleetwood Mac (Peter Green???) and they've just kept that green thing running.
Again, all of this could be lies...but that was how I understood things.