Once again this board spouts off with warnings not to ever do (fill in the blank) or you will regret it. And once again, they have no evidence to support the claim. What BS!!! Metal particles, galvanic corrosion, more noble/less noble, this stuff just does not apply to an AR15. Just people repeating what they heard somewhere else and know nothing of the subject.
Lube the threads and you will suffer no ill. None. Not any. Zip (think of Monty Python and the dead parrot here). Any antiseize will do just fine. Any lithium based grease, any Moly based grease. It just does not matter. I personally still use Lubi-plate and love the stuff. Been building and repairing engines of all types for 40+ years and it never, not once, failed me.
Combat weapons should be welded together and never take apart further then is necessary for cleaning. When broken, crush the gun and get a new issue. Combat is different. Yours is not a combat weapon. You may actually want to change the buttstock, handguard, whatever, someday. Make it easy on yourself.