Why would they have painted it already? I could understand if another Korean frame was the previous frame and the paint colour and templates would already be in place. Airbus could have one paint shop devoted to Emirates frames and one for other frames to improve efficiency.
Airbus seems to be introducing alternative sequences of work in order to reduce overall lead times. Painting is performed at different stages : most frames are still painted after outfitting, but sometimes painting is performed before outfitting, and at least one frame had CFF before being painted.