don't have the advantage of being able to smell, feel, etc this thick film...
if it was me... I'd clean it out before installing it. I've not seen a need for lube in that area.
now "IF" some type of thread locker... I'd remove it too.... the spanner nut should retain the tube just fine when torqued (and staked), though "I" give it some thought befoe doing so in the event i want to make some immediate changes.
good luck with the build.