Installing new dipstick tube adapter to new oil pan

I bought a new Ford o ring, nut, and adapter for my new moroso oil pan. My question is, do I have to use loctite 515 on the threads? The kit from diesel orings also has a flat gasket to seal the nut. Do I really need this? Also I have some Ford grey rtv, wondering if I should put some on the oring to help seal and keep the o ring in place.

I used the gasket and I put a very thin layer on both sides and I mean thin if you use it and the ford grey and get it to thick the nut wont even start to thread. I used the locktite on the threads and just used a smidge of grease on the oring. I used the exact same parts on a new oil pan install with new nut and adaptor