Rear diff <> prop shaft - can I reuse the nut?

[rodnex]

Hey folks,

I want to try our a different gearing ratio, hence I want to swap diffs.
As per BMW I need to replace the nut...

But neither do I have the nut now at hands nor did I want to spend 50 bucks just for a nut which I am going to unscrew after a week.

Anybody re-used it before?

Thanks for your feedback
Rod