Im not sure how to answer that. If you use a LUT and render out Render Elements, each element gets the LUT applied, and when comped will not look like the Beauty pass.
What I would want to see is either the LUT is only applied to the Beauty pass, and the elements are spit out without the LUT.
Or..........
The LUT is applied to the elements in a way so that when composited back, it matches the beauty. (This may not be possible with how the LUTs are used I dont know).
Right now you can just test for yourself with you Benchmark scene. Render it with a LUT and all Essential Render Elements. Then comp them in Nuke to see the difference.