The ones that count will be underneath the bearings, so I don't think you can see them without dismantling the shaft from the housing. It might take a few tries to get it right: with the nut tight, there is no drag from the bearings when you rotate the shaft, but no noticeable axial movement of the shaft due to sliding the bearing outers up and down in the housing.
Some pictures of the housing and the various parts would help make this thread useful in our archives.
