To answer your question - yes, it does matter whether the calories come from carbs or other sources. In the context of glycolytic, anaerobic work (like resistance training), carb intake becomes more critical as you increase training frequency, training volume, and training intensity.
Yes, the overfed state contributes to the overall anabolic environment, but it's primarily the carbohydrates that fuel the training, and primarily the protein that supports the adaptation to the training.
Yes, fat is important for overall health, but the protein and carbs are the workhorses here.
Of course, different people need different amounts dependent on their genetics, training volume, and dietary history. However, you can shove fat down your gullet to create all the caloric surplus you want but you'll likely get nowhere if you aren't giving your body the carbs it needs to perform glycolytic work and the protein it needs to recover.
Does that make sense?