Curious what the opinion is on the need to seal the CVT back cover to the engine/trans? Also how many are reusing the cover gasket?

I just installed my QSC clutch kit and thought that I had a cover gasket, but I had the wrong part in the package so I put it back together. If there is a true need to seal things up I’ll pull the whole shebang back apart and do it once I’m sure that I’m liking the clutching weight setup.