Give user the possibility (in the Style) to define a specific style for dimensions and annotations driven from the model.
So if a annotation is retrieved from the model it should be highlighted in a different style like the one created manually. See in the picture below, the 2 different styles (from another CAD system). User can directly identify the annotations coming from the model and the one set manually in the drawing.

This will get more and more importance the more users are working with model annotations.