It all makes sense. There is a crashed highwayman next to Novac, which was the Chosen One's car. It was said that a radscorpion sting made No-Bark all looney, what if he became delirious and crashed his car next to Novac then forgot everything about himself? It makes sense, really. No-Bark is around 60 years old. Fallout:NV takes place 40 years after Fallout 2. No-Bark is surprisingly aware of everything going on around him, he knows who is killing the Brahmin and he knows about the Bright Brotherhood. He is almost as aware of the events going around him as a player character. Play No-Bark in Caravan and he will have 1000 caps. How does a crack-pot like No Bark have this many caps? He got it from his adventures as the Chosen One. I will continue to add onto this theory tommorow, and remember that this is all a joke.