Don't worry about it...
Don't worry about copying another pattern, it happens to me all the time. Your right about the regional difference when it comes to fly's. Look at the needle fish patterns from Alaska compared to the sand eel patterns from the east coast. There the same fly but have different names.
The Damsel fly I tied, which I thought was origional, turned out to be a pattern that's been used for 20 years. If you took the time to research every fly you tie by every possible discription you wouldn't have much time at the vice.
I know we need to give credit where credit is due, but if you think about it every time we tie hackle and dubbing around a hook were just creating varaitions of the origional dry or nymph.
Just my 2 centts....