In my experience the willingness of a summer steelhead to come to a surface fly is less dependent on whether they are hatchery or wild but rather the fish's condition. The biggest key is whether the fish or traveling or not. In my fishing in the Puget Sound region when I could find hatchery fish that were still traveling upstream the seem to come readily to the surface. The fish that have podded up in up-river holding pools were difficult to move. However those up-river fish would come to the surface after they were "stirred up" after the first fall rains. Have had excellent fall (late September/October) fishing with waking caddis on hatchery fish on Stilli, Sky and Snoqualmie. The fishing was usually for only a day or two on the drop following a good river rise which seem to move the fish around. Once the fish settled down they seemed to go stale again; at least for surface activity.
Believe whether the fish are moving or not explains much of why the hatchery fish on the East-side of Cascades seem to come to the surface better. In the Puget Sound area by the time the rivers clear and drop to good waking conditions (mid-July?) most of the hatchery fish are all ready in up river areas and not moving much. However the wild fish (example the wonderful Deer Creek fish) are just starting to arrive in good numbers.
Another factor is whether the hatchery fish are being pressured or not. Whenever I could find summer steelhead (hatchey or wild) that have not been fished much good fishing was found. The fish in runs or glides (less than 6 feet deep is key) would respond to surface methods the best. Unfortunately it is getting pretty difficult to find such fish.
Just my observations.