Yup the General will always have the RB50.
GP is "Glass Polarizing" a small run of Bausch and Lomb have Polarized lenses, little GP under the Ray Ban logo. Pretty rare (I want a pair) :)
Off Road-One is another special spin off edition. Again, bigger in Malaysia. They did a few special ones for some companies. I'm pretty sure the Off road ones are for the G15 driving series in early 90's.
Fantansees is a hard one... Some of them will have "Fantasees" on the right hand lens up the top. Those that don't, its hard to tell! Other than the fact they are the quickest of all the Bausch and Lomb lenses to darken. They came with a very specific case and box,the lenses are tinted at the top and pretty light.
I don't have much info on the white golds really, you don't see many of them around so yeah pretty rare. I think there is quite a stretch of them in terms of time as I've seen them with quite a few different era marks. I'll have a little hunt and see if I can find out more.