HELP - K2 Rear Drive Shafts & Stuff

[Spanky855]

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Hi All

30 years since I have raced and have just bought a second hand K2 which looks in good condition but I am stripping down, checking parts and the build construction. Attached are two images on the left and right rear drive shaft, can anyones tell me why the pin is shorter in one of them, its not worn or broken, the only thing I can thing of is its a manufacturing fault? Thoughts please guys and girls would be appreciated,