They look identical except for the missing part. The two large holes on the topside look like they are different size but I think those are for using a puller. Someone correct me if I am wrong- do not want to mislead anyone.
After closer examination I notice that the one on the left has a notch down the side of the splines and the one on the right does not. Does this make a difference and if so which one will fit correctly on a 72 column.