Yeah that is the correct recipe for the Eternal Armor and you don't need the recipe to craft it.
The armor will scale to your character level when you craft it, it is by far the most powerful Knight/heavy chest plate in the game. You can also find enough ingredients to craft it about 8 times
Also to add to your list is the unique 2H Scythe "Swornbreaker"
Requires the Recipe (Picked up in act 2) + Haft of the Swornbreaker + Blade of the Swornbreaker (Both found on Nameless Isle)
"Swornbreaker" skill is related to a quest granted by either Almira or Ryker. Ryker is the one who wants the tablet (recipe) for it, Almira wants you to craft it for her and give her the weapon. The item itself will disappear upon using the "Swornbreaker" skill.