I fear a subtlety of the word "pattern" is being lost here. Think of a suit. A pattern defines the features - e.g. there are pockets, arms, legs etc. However, it doesn't define every single detail of how it is put together (buttons, fabric, lining etc) - this is left to the implementer.
Yes, for a lot of design patterns there is boilerplate code many of us tend to use, but for others, there is more than one way of achieving the pattern with no generally agreed method.