I would hazard a guess that the star mark on the end of that shaft is from production, the spline tool would have to rotate that shaft without slipping while it cut the spine. As to which way round it makes for good practice to install drive shafts in the same rotation as they came off so as not to cause fatigue in the material. From new it would make no difference and I dont think I would lose any sleep if they swapped rotation in a car that weighed the same as a bag of sugar. 44ton truck maybe
Bob