I agree with making the Raiders not hidden, but using the smallest circle size. I also noticed that when I completed Fallout 2, only 16 of the 17 main locations were labeled. Presumably the Raiders base is the 17th, since it was the only other location with a town map screen. I think it might not have gotten a label because it was changed to a hidden location. When I used Bishop's map it should have been added. From what I've read here it seems that it was intentionally left as non-hidden in the final release, even though that may not always have been the case.