When I removed mine to check the foam, which was absent, and drill gasket holes, I used Loctite when replacing them. Didn’t know if it was correct but intuition suggested it might be sensible.
The only thing I wondered was whether it would bond, given the oil which, despite my cleaning efforts, was in all of the threads.
It was irrelevant in the end because both were subsequently removed by Dave Andrews for bottom end work and I’m sure he would have done whatever is best when re- fixing.