If you are doing t he clutch splines you might want to do the clutch o-ring and the rear main seal on the engine, the one behind the clutch assembly. If that is your plan, you have the correct part number.
You can also get the seal and o-ring at an industrial bearing/seal distributor. The seal is teflon, size 50x80x10. The O-ring is viton and the size is 19x4