If they have survived/resided, you should be able to find plenty of RT "fingerlings" that were stocked in the fall. If those "fingerlings" were as large as last year's when stocked, they were 7.25 inches when stocked and by this time last year some were reported to be 8.5-9 inches long.
There is also a substantial wild brown trout population developing....Class A equivalent this past summer. This is occurring despite continued stocking. Granted, the stockings are "fingerlings," but this is only a technicality since the fish are small adult size. Additionally, the "fingerlings" are being stocked in much higher numbers than the adults used to be, so the recent cessation of adult trout stocking in Donegal has nothing to do with the Class A equivalent brown trout population's development, as the response in the wild brown trout population would have been too quick relative to the timing of the last adult stocking's effect. Clearly, the wild browns were already present in similar abundance when the last adults were stocked in spring, 2012. A stream does not go from mediocre to a Class A equivalent in one year.
So there is some history for you. All RT stocked in the past two falls as "fingerlings" have the adipose fin removed. Good luck if you make the trip.