Actually there are several creeks which hold good populations of browns in our local mountains. I'm not too familar with Rock Creek but the possibility of catching a brown in So Cal creeks is better then most would expect. Not much size to the fish but at least they are there. It's also possible that the DFG could have put some in to the Creek to see if they would establish a population seeing as they have done well in other waters similar to rock creek. I remember back in the day Silverwood was place in So Cal known for holding some nice browns. The biggest one I had ever seen caught there was about 5lbs(late 70's). Once the stripers took hold the browns disapeared and the stripers got big.

JerryG