Nope, not needed. You can take off any mechanism on the back of the engine. Threads might be left hand...

When I am feeling ambitious, I cut the crank off just inside the rear bearing. Then I make a plug to go where the seal was. Loses a little bit of weight done like that, and there is one less place for the engine to possibly leak, but it is a bit "overboard" and not necessary.

AV8TOR