In the lower part of Road Prong, accessible from WPLP, there are, indeed, bows just as you will find them in Sams Creek below the falls. From the fourth bridge of the Chimneys Trail and up, you will not find a single rainbow. Specs rule. So somewhere between the second bridge and the fourth is the unscalable natural barrier that keeps bows out of the upper reaches. If I'm not mistaken, Road Prong was a closed stream up until a few years ago and my assumption was that this was for a restoration project.
Like Bear Creek, a little known TU restoration project of a few years back was Mannis Branch. Bows have been replaced by specs there as well. Mannis is a skinny creek from its lowest reaches and not the draw that many other streams are but I've been assured that it is full of specs, particularly in its upper waters.
His eye is on the sparrow and I know He watches me.