As Mike says , they are not all the same. Besides nose bearing differences the prop bushings can also vary. It basically boils down to shafts that can be operated constant speed and those that can't. If you are buying a shaft from a parts supplier they should know the difference and be able to get you the correct shaft. If you are buying used, on the open market, get a parts book and don't get anything other then the shafts listed or superceded to your engine.
Good Luck,
Mahlon
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