No there is no proof, but the inference is very strong.
If they don't draw conclusions (at least) that fatigue likely contributed to this accident, I ask what further signs would be required to assign likely cause to fatigue?
I haven't heard that Emirates are looking at bringing their flight/duty limits closer to international standard practices. The capt was on 98.9 hrs at the start of the duty, and would have been 114 on arrival, not legal under most work practices.